# `xml.etree.ElementTree` — L'API ElementTree XML

Code Source: Lib/xml/etree/ElementTree.py

Le module `xml.etree.ElementTree` implémente une API simple et efficace pour analyser et créer des données XML.

Modifié dans la version 3.3: This module will use a fast implementation whenever available. The `xml.etree.cElementTree` module is deprecated.

Avertissement

The `xml.etree.ElementTree` module is not secure against maliciously constructed data. If you need to parse untrusted or unauthenticated data see Vulnérabilités XML.

## Tutoriel

Ceci est un petit tutoriel pour utiliser `xml.etree.ElementTree` (`ET`). Le but est de démontrer quelques composants et les concepts basiques du module.

### Arborescence et éléments XML

XML est un format de données fondamentalement hiérarchique et la façon la plus naturelle de la représenter est avec un arbre. `ET` a deux classes pour ce but- `ElementTree` représente l'ensemble du document XML comme un arbre et `Element` est représenté en tant que nœud dans cet arbre. Les interactions (lire et écrire vers/depuis des fichiers) sur le document sont habituellement effectués au niveau de `ElementTree`. Les interactions sur un seul élément XML et ses sous-éléments sont effectués au niveau de `Element`.

### Analyse XML

Nous utilisons le document XML suivant comme exemple pour cette section :

    <?xml version="1.0"?>
    <data>
        <country name="Liechtenstein">
            <rank>1</rank>
            <year>2008</year>
            <gdppc>141100</gdppc>
            <neighbor name="Austria" direction="E"/>
            <neighbor name="Switzerland" direction="W"/>
        </country>
        <country name="Singapore">
            <rank>4</rank>
            <year>2011</year>
            <gdppc>59900</gdppc>
            <neighbor name="Malaysia" direction="N"/>
        </country>
        <country name="Panama">
            <rank>68</rank>
            <year>2011</year>
            <gdppc>13600</gdppc>
            <neighbor name="Costa Rica" direction="W"/>
            <neighbor name="Colombia" direction="E"/>
        </country>
    </data>

Nous pouvons importer cette donnée en lisant un fichier :

    import xml.etree.ElementTree as ET
    tree = ET.parse('country_data.xml')
    root = tree.getroot()

Ou depuis une chaîne de caractères :

    root = ET.fromstring(country_data_as_string)

`fromstring()` analyse le XML depuis une chaîne de caractères vers un `Element`, ce dernier est l'élément racine de l'arbre analysé. D'Autres fonctions d'analyse peuvent créer un `ElementTree`. Vérifier la documentation pour être sûr.

Comme `Element`, `root` a une balise et un dictionnaire d'attributs :

    >>> root.tag
    'data'
    >>> root.attrib
    {}

Il contient aussi des nœuds enfants que nous pouvons itérer :

    >>> for child in root:
    ...     print(child.tag, child.attrib)
    ...
    country {'name': 'Liechtenstein'}
    country {'name': 'Singapore'}
    country {'name': 'Panama'}

Les enfants sont imbriqués et nous pouvons accéder aux nœuds enfants spécifiques via un index :

    >>> root[0][1].text
    '2008'

Note

Les éléments du XML d'entrée ne sont pas tous considérés comme des éléments de l'arborescence. Souvent, le module ignore les commentaires XML, les instructions de traitements et la déclaration du type de document dans l'entrée. Néanmoins, les arborescences sont construites en utilisant l'API du module plutôt que d'analyser depuis un texte XML qui peut contenir des commentaires et des instructions de traitements ; ils peuvent être inclus lors de la génération du XML de sortie. Le type de déclaration du document est accessible en passant par une instance de `TreeBuilder` dans le constructeur de `XMLParser`.

### API à flux tiré

Most parsing functions provided by this module require the whole document to be read at once before returning any result. It is possible to use an `XMLParser` and feed data into it incrementally, but it is a push API that calls methods on a callback target, which is too low-level and inconvenient for most needs. Sometimes what the user really wants is to be able to parse XML incrementally, without blocking operations, while enjoying the convenience of fully constructed `Element` objects.

The most powerful tool for doing this is `XMLPullParser`. It does not require a blocking read to obtain the XML data, and is instead fed with data incrementally with `XMLPullParser.feed()` calls. To get the parsed XML elements, call `XMLPullParser.read_events()`. Here is an example:

    >>> parser = ET.XMLPullParser(['start', 'end'])
    >>> parser.feed('<mytag>sometext')
    >>> list(parser.read_events())
    [('start', <Element 'mytag' at 0x7fa66db2be58>)]
    >>> parser.feed(' more text</mytag>')
    >>> for event, elem in parser.read_events():
    ...     print(event)
    ...     print(elem.tag, 'text=', elem.text)
    ...
    end

The obvious use case is applications that operate in a non-blocking fashion where the XML data is being received from a socket or read incrementally from some storage device. In such cases, blocking reads are unacceptable.

Because it's so flexible, `XMLPullParser` can be inconvenient to use for simpler use-cases. If you don't mind your application blocking on reading XML data but would still like to have incremental parsing capabilities, take a look at `iterparse()`. It can be useful when you're reading a large XML document and don't want to hold it wholly in memory.

### Trouver les éléments d'intérêt

`Element` a quelques méthodes très utiles qui aident à parcourir récursivement tous les sous-arbres (ses enfants, leurs enfants et ainsi de suite). Par exemple, `Element.iter()` :

    >>> for neighbor in root.iter('neighbor'):
    ...     print(neighbor.attrib)
    ...
    {'name': 'Austria', 'direction': 'E'}
    {'name': 'Switzerland', 'direction': 'W'}
    {'name': 'Malaysia', 'direction': 'N'}
    {'name': 'Costa Rica', 'direction': 'W'}
    {'name': 'Colombia', 'direction': 'E'}

`Element.findall()` récupère seulement les éléments avec une balise qui sont les descendants directs de l'élément courant. `Element.find()` récupère le premier élément avec une balise particulière et `Element.text` accède au contenu textuel de l'élément. `Element.get()` accède aux attributs de l'élément :

    >>> for country in root.findall('country'):
    ...     rank = country.find('rank').text
    ...     name = country.get('name')
    ...     print(name, rank)
    ...
    Liechtenstein 1
    Singapore 4
    Panama 68

More sophisticated specification of which elements to look for is possible by using XPath.

### Modification d'un fichier XML

`ElementTree` provides a simple way to build XML documents and write them to files. The `ElementTree.write()` method serves this purpose.

Once created, an `Element` object may be manipulated by directly changing its fields (such as `Element.text`), adding and modifying attributes (`Element.set()` method), as well as adding new children (for example with `Element.append()`).

Let's say we want to add one to each country's rank, and add an `updated` attribute to the rank element:

    >>> for rank in root.iter('rank'):
    ...     new_rank = int(rank.text) + 1
    ...     rank.text = str(new_rank)
    ...     rank.set('updated', 'yes')
    ...
    >>> tree.write('output.xml')

Maintenant, notre XML ressemble à ceci :

    <?xml version="1.0"?>
    <data>
        <country name="Liechtenstein">
            <rank updated="yes">2</rank>
            <year>2008</year>
            <gdppc>141100</gdppc>
            <neighbor name="Austria" direction="E"/>
            <neighbor name="Switzerland" direction="W"/>
        </country>
        <country name="Singapore">
            <rank updated="yes">5</rank>
            <year>2011</year>
            <gdppc>59900</gdppc>
            <neighbor name="Malaysia" direction="N"/>
        </country>
        <country name="Panama">
            <rank updated="yes">69</rank>
            <year>2011</year>
            <gdppc>13600</gdppc>
            <neighbor name="Costa Rica" direction="W"/>
            <neighbor name="Colombia" direction="E"/>
        </country>
    </data>

We can remove elements using `Element.remove()`. Let's say we want to remove all countries with a rank higher than 50:

    >>> for country in root.findall('country'):
    ...     # using root.findall() to avoid removal during traversal
    ...     rank = int(country.find('rank').text)
    ...     if rank > 50:
    ...         root.remove(country)
    ...
    >>> tree.write('output.xml')

Note that concurrent modification while iterating can lead to problems, just like when iterating and modifying Python lists or dicts. Therefore, the example first collects all matching elements with `root.findall()`, and only then iterates over the list of matches.

Maintenant, notre XML ressemble à ceci :

    <?xml version="1.0"?>
    <data>
        <country name="Liechtenstein">
            <rank updated="yes">2</rank>
            <year>2008</year>
            <gdppc>141100</gdppc>
            <neighbor name="Austria" direction="E"/>
            <neighbor name="Switzerland" direction="W"/>
        </country>
        <country name="Singapore">
            <rank updated="yes">5</rank>
            <year>2011</year>
            <gdppc>59900</gdppc>
            <neighbor name="Malaysia" direction="N"/>
        </country>
    </data>

### Création de documents XML

The `SubElement()` function also provides a convenient way to create new sub-elements for a given element:

    >>> a = ET.Element('a')
    >>> b = ET.SubElement(a, 'b')
    >>> c = ET.SubElement(a, 'c')
    >>> d = ET.SubElement(c, 'd')
    >>> ET.dump(a)
    <a><b /><c><d /></c></a>

### Analyse d'un XML avec des espaces de noms

If the XML input has namespaces, tags and attributes with prefixes in the form `prefix:sometag` get expanded to `{uri}sometag` where the prefix is replaced by the full URI. Also, if there is a default namespace, that full URI gets prepended to all of the non-prefixed tags.

Here is an XML example that incorporates two namespaces, one with the prefix "fictional" and the other serving as the default namespace:

    <?xml version="1.0"?>
    <actors xmlns:fictional="http://characters.example.com"
            xmlns="http://people.example.com">
        <actor>
            <name>John Cleese</name>
            <fictional:character>Lancelot</fictional:character>
            <fictional:character>Archie Leach</fictional:character>
        </actor>
        <actor>
            <name>Eric Idle</name>
            <fictional:character>Sir Robin</fictional:character>
            <fictional:character>Gunther</fictional:character>
            <fictional:character>Commander Clement</fictional:character>
        </actor>
    </actors>

One way to search and explore this XML example is to manually add the URI to every tag or attribute in the xpath of a `find()` or `findall()`:

    root = fromstring(xml_text)
    for actor in root.findall('{http://people.example.com}actor'):
        name = actor.find('{http://people.example.com}name')
        print(name.text)
        for char in actor.findall('{http://characters.example.com}character'):
            print(' |-->', char.text)

A better way to search the namespaced XML example is to create a dictionary with your own prefixes and use those in the search functions:

    ns = {'real_person': 'http://people.example.com',
          'role': 'http://characters.example.com'}

    for actor in root.findall('real_person:actor', ns):
        name = actor.find('real_person:name', ns)
        print(name.text)
        for char in actor.findall('role:character', ns):
            print(' |-->', char.text)

Ces deux approches donnent le même résultat :

    John Cleese
     |--> Lancelot
     |--> Archie Leach
    Eric Idle
     |--> Sir Robin
     |--> Gunther
     |--> Commander Clement

### Additional resources

See http://effbot.org/zone/element-index.htm for tutorials and links to other docs.

## Prise en charge de XPath

This module provides limited support for XPath expressions for locating elements in a tree. The goal is to support a small subset of the abbreviated syntax; a full XPath engine is outside the scope of the module.

### Exemple

Here's an example that demonstrates some of the XPath capabilities of the module. We'll be using the `countrydata` XML document from the Parsing XML section:

    import xml.etree.ElementTree as ET

    root = ET.fromstring(countrydata)

    # Top-level elements
    root.findall(".")

    # All 'neighbor' grand-children of 'country' children of the top-level
    # elements
    root.findall("./country/neighbor")

    # Nodes with name='Singapore' that have a 'year' child
    root.findall(".//year/..[@name='Singapore']")

    # 'year' nodes that are children of nodes with name='Singapore'
    root.findall(".//*[@name='Singapore']/year")

    # All 'neighbor' nodes that are the second child of their parent
    root.findall(".//neighbor[2]")

For XML with namespaces, use the usual qualified `{namespace}tag` notation:

    # All dublin-core "title" tags in the document
    root.findall(".//{http://purl.org/dc/elements/1.1/}title")

### Prise en charge de la syntaxe XPath

Syntaxe | Signification
--- | ---
`tag` | Sélectionne tous les éléments enfants avec une balise donnée. Par exemple, `spam` sélectionne tous les éléments enfants nommés `spam` et `spam/egg` sélectionne tous les petits-enfants nommés `egg` dans les enfants nommés `spam`. `{namespace}*` sélectionne toutes les balises dans l'espace de nom donné, `{*}spam` sélectionne les balises nommées `spam` dans n'importe quel (ou aucun) espace de nom et `{}*` sélectionne seulement les balises qui ne sont pas dans un espace de nom. Modifié dans la version 3.8: Support for star-wildcards was added.
`*` | Selects all child elements, including comments and processing instructions. For example, `*/egg` selects all grandchildren named `egg`.
`.` | Selects the current node. This is mostly useful at the beginning of the path, to indicate that it's a relative path.
`//` | Selects all subelements, on all levels beneath the current element. For example, `.//egg` selects all `egg` elements in the entire tree.
`..` | Selects the parent element. Returns `None` if the path attempts to reach the ancestors of the start element (the element `find` was called on).
`[@attrib]` | Selects all elements that have the given attribute.
`[@attrib='value']` | Selects all elements for which the given attribute has the given value. The value cannot contain quotes.
`[tag]` | Selects all elements that have a child named `tag`. Only immediate children are supported.
`[.='text']` | Selects all elements whose complete text content, including descendants, equals the given `text`. Nouveau dans la version 3.7.
`[tag='text']` | Selects all elements that have a child named `tag` whose complete text content, including descendants, equals the given `text`.
`[position]` | Selects all elements that are located at the given position. The position can be either an integer (1 is the first position), the expression `last()` (for the last position), or a position relative to the last position (e.g. `last()-1`).

Predicates (expressions within square brackets) must be preceded by a tag name, an asterisk, or another predicate. `position` predicates must be preceded by a tag name.

## Référence

### Fonctions

`xml.etree.ElementTree.``canonicalize`(xml_data=None, *, out=None, from_file=None, **options)

  C14N 2.0 fonction de transformation.

  Canonicalization is a way to normalise XML output in a way that allows byte-by-byte comparisons and digital signatures. It reduced the freedom that XML serializers have and instead generates a more constrained XML representation. The main restrictions regard the placement of namespace declarations, the ordering of attributes, and ignorable whitespace.

  This function takes an XML data string (xml_data) or a file path or file-like object (from_file) as input, converts it to the canonical form, and writes it out using the out file(-like) object, if provided, or returns it as a text string if not. The output file receives text, not bytes. It should therefore be opened in text mode with `utf-8` encoding.

  Typical uses:

      xml_data = "<root>...</root>"
      print(canonicalize(xml_data))

      with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
          canonicalize(xml_data, out=out_file)

      with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
          canonicalize(from_file="inputfile.xml", out=out_file)

  Les options de configuration sont les suivantes :

  - with_comments : attribue à vrai pour inclure les commentaires (par défaut : faux)

  - strip_text: set to true to strip whitespace before and after text content

      (par défaut : faux)

  - rewrite_prefixes: set to true to replace namespace prefixes by "n{number}"

      (par défaut : faux)

  - qname_aware_tags: a set of qname aware tag names in which prefixes

      should be replaced in text content (default: empty)

  - qname_aware_attrs: a set of qname aware attribute names in which prefixes

      should be replaced in text content (default: empty)

  - exclude_attrs: a set of attribute names that should not be serialised

  - exclude_tags: a set of tag names that should not be serialised

  In the option list above, "a set" refers to any collection or iterable of strings, no ordering is expected.

  Nouveau dans la version 3.8.

`xml.etree.ElementTree.``Comment`(text=None)

  Comment element factory. This factory function creates a special element that will be serialized as an XML comment by the standard serializer. The comment string can be either a bytestring or a Unicode string. text is a string containing the comment string. Returns an element instance representing a comment.

  Note that `XMLParser` skips over comments in the input instead of creating comment objects for them. An `ElementTree` will only contain comment nodes if they have been inserted into to the tree using one of the `Element` methods.

`xml.etree.ElementTree.``dump`(elem)

  Writes an element tree or element structure to sys.stdout. This function should be used for debugging only.

  The exact output format is implementation dependent. In this version, it's written as an ordinary XML file.

  elem est un élément de l'arborescence ou un élément individuel.

  Modifié dans la version 3.8: The `dump()` function now preserves the attribute order specified by the user.

`xml.etree.ElementTree.``fromstring`(text, parser=None)

  Parses an XML section from a string constant. Same as `XML()`. text is a string containing XML data. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. Returns an `Element` instance.

`xml.etree.ElementTree.``fromstringlist`(sequence, parser=None)

  Parses an XML document from a sequence of string fragments. sequence is a list or other sequence containing XML data fragments. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. Returns an `Element` instance.

  Nouveau dans la version 3.2.

`xml.etree.ElementTree.``iselement`(element)

  Check if an object appears to be a valid element object. element is an element instance. Return `True` if this is an element object.

`xml.etree.ElementTree.``iterparse`(source, events=None, parser=None)

  Parses an XML section into an element tree incrementally, and reports what's going on to the user. source is a filename or file object containing XML data. events is a sequence of events to report back. The supported events are the strings `"start"`, `"end"`, `"comment"`, `"pi"`, `"start-ns"` and `"end-ns"` (the "ns" events are used to get detailed namespace information). If events is omitted, only `"end"` events are reported. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. parser must be a subclass of `XMLParser` and can only use the default `TreeBuilder` as a target. Returns an iterator providing `(event, elem)` pairs.

  Note that while `iterparse()` builds the tree incrementally, it issues blocking reads on source (or the file it names). As such, it's unsuitable for applications where blocking reads can't be made. For fully non-blocking parsing, see `XMLPullParser`.

  Note

  `iterparse()` only guarantees that it has seen the ">" character of a starting tag when it emits a "start" event, so the attributes are defined, but the contents of the text and tail attributes are undefined at that point. The same applies to the element children; they may or may not be present.

  If you need a fully populated element, look for "end" events instead.

  Obsolète depuis la version 3.4: L'argument parser.

  Modifié dans la version 3.8: Les évènements `comment` et `pi` ont été ajoutés.

`xml.etree.ElementTree.``parse`(source, parser=None)

  Parses an XML section into an element tree. source is a filename or file object containing XML data. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. Returns an `ElementTree` instance.

`xml.etree.ElementTree.``ProcessingInstruction`(target, text=None)

  PI element factory. This factory function creates a special element that will be serialized as an XML processing instruction. target is a string containing the PI target. text is a string containing the PI contents, if given. Returns an element instance, representing a processing instruction.

  Note that `XMLParser` skips over processing instructions in the input instead of creating comment objects for them. An `ElementTree` will only contain processing instruction nodes if they have been inserted into to the tree using one of the `Element` methods.

`xml.etree.ElementTree.``register_namespace`(prefix, uri)

  Registers a namespace prefix. The registry is global, and any existing mapping for either the given prefix or the namespace URI will be removed. prefix is a namespace prefix. uri is a namespace uri. Tags and attributes in this namespace will be serialized with the given prefix, if at all possible.

  Nouveau dans la version 3.2.

`xml.etree.ElementTree.``SubElement`(parent, tag, attrib={}, **extra)

  Subelement factory. This function creates an element instance, and appends it to an existing element.

  The element name, attribute names, and attribute values can be either bytestrings or Unicode strings. parent is the parent element. tag is the subelement name. attrib is an optional dictionary, containing element attributes. extra contains additional attributes, given as keyword arguments. Returns an element instance.

`xml.etree.ElementTree.``tostring`(element, encoding="us-ascii", method="xml", *, xml_declaration=None, default_namespace=None, short_empty_elements=True)

  Generates a string representation of an XML element, including all subelements. element is an `Element` instance. encoding 1 is the output encoding (default is US-ASCII). Use `encoding="unicode"` to generate a Unicode string (otherwise, a bytestring is generated). method is either `"xml"`, `"html"` or `"text"` (default is `"xml"`). xml_declaration, default_namespace and short_empty_elements has the same meaning as in `ElementTree.write()`. Returns an (optionally) encoded string containing the XML data.

  Nouveau dans la version 3.4: Le paramètre short_empty_elements.

  Nouveau dans la version 3.8: Les paramètres xml_declaration et default_namespace.

  Modifié dans la version 3.8: The `tostring()` function now preserves the attribute order specified by the user.

`xml.etree.ElementTree.``tostringlist`(element, encoding="us-ascii", method="xml", *, xml_declaration=None, default_namespace=None, short_empty_elements=True)

  Generates a string representation of an XML element, including all subelements. element is an `Element` instance. encoding 1 is the output encoding (default is US-ASCII). Use `encoding="unicode"` to generate a Unicode string (otherwise, a bytestring is generated). method is either `"xml"`, `"html"` or `"text"` (default is `"xml"`). xml_declaration, default_namespace and short_empty_elements has the same meaning as in `ElementTree.write()`. Returns a list of (optionally) encoded strings containing the XML data. It does not guarantee any specific sequence, except that `b"".join(tostringlist(element)) == tostring(element)`.

  Nouveau dans la version 3.2.

  Nouveau dans la version 3.4: Le paramètre short_empty_elements.

  Nouveau dans la version 3.8: Les paramètres xml_declaration et default_namespace.

  Modifié dans la version 3.8: The `tostringlist()` function now preserves the attribute order specified by the user.

`xml.etree.ElementTree.``XML`(text, parser=None)

  Parses an XML section from a string constant. This function can be used to embed "XML literals" in Python code. text is a string containing XML data. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. Returns an `Element` instance.

`xml.etree.ElementTree.``XMLID`(text, parser=None)

  Parses an XML section from a string constant, and also returns a dictionary which maps from element id:s to elements. text is a string containing XML data. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. Returns a tuple containing an `Element` instance and a dictionary.

## Prise en charge de XInclude

This module provides limited support for XInclude directives, via the `xml.etree.ElementInclude` helper module. This module can be used to insert subtrees and text strings into element trees, based on information in the tree.

### Exemple

Here's an example that demonstrates use of the XInclude module. To include an XML document in the current document, use the `{http://www.w3.org/2001/XInclude}include` element and set the parse attribute to `"xml"`, and use the href attribute to specify the document to include.

    <?xml version="1.0"?>
    <document xmlns:xi="http://www.w3.org/2001/XInclude">
      <xi:include href="source.xml" parse="xml" />
    </document>

By default, the href attribute is treated as a file name. You can use custom loaders to override this behaviour. Also note that the standard helper does not support XPointer syntax.

To process this file, load it as usual, and pass the root element to the `xml.etree.ElementTree` module:

    from xml.etree import ElementTree, ElementInclude

    tree = ElementTree.parse("document.xml")
    root = tree.getroot()

    ElementInclude.include(root)

The ElementInclude module replaces the `{http://www.w3.org/2001/XInclude}include` element with the root element from the source.xml document. The result might look something like this:

    <document xmlns:xi="http://www.w3.org/2001/XInclude">
      <para>This is a paragraph.</para>
    </document>

If the parse attribute is omitted, it defaults to "xml". The href attribute is required.

To include a text document, use the `{http://www.w3.org/2001/XInclude}include` element, and set the parse attribute to "text":

    <?xml version="1.0"?>
    <document xmlns:xi="http://www.w3.org/2001/XInclude">
      Copyright (c) <xi:include href="year.txt" parse="text" />.
    </document>

The result might look something like:

    <document xmlns:xi="http://www.w3.org/2001/XInclude">
      Copyright (c) 2003.
    </document>

## Référence

### Fonctions

`xml.etree.ElementInclude.``default_loader`(href, parse, encoding=None)

  Default loader. This default loader reads an included resource from disk. href is a URL. parse is for parse mode either "xml" or "text". encoding is an optional text encoding. If not given, encoding is `utf-8`. Returns the expanded resource. If the parse mode is `"xml"`, this is an ElementTree instance. If the parse mode is "text", this is a Unicode string. If the loader fails, it can return None or raise an exception.

`xml.etree.ElementInclude.``include`(elem, loader=None)

  This function expands XInclude directives. elem is the root element. loader is an optional resource loader. If omitted, it defaults to `default_loader()`. If given, it should be a callable that implements the same interface as `default_loader()`. Returns the expanded resource. If the parse mode is `"xml"`, this is an ElementTree instance. If the parse mode is "text", this is a Unicode string. If the loader fails, it can return None or raise an exception.

### Objets Elements

class `xml.etree.ElementTree.``Element`(tag, attrib={}, **extra)

  Classe Element. Cette classe définit l'interface Element et fournit une implémentation de référence de cette interface.

  The element name, attribute names, and attribute values can be either bytestrings or Unicode strings. tag is the element name. attrib is an optional dictionary, containing element attributes. extra contains additional attributes, given as keyword arguments.

  `tag`

    A string identifying what kind of data this element represents (the element type, in other words).

  `text`
  `tail`

    These attributes can be used to hold additional data associated with the element. Their values are usually strings but may be any application-specific object. If the element is created from an XML file, the text attribute holds either the text between the element's start tag and its first child or end tag, or `None`, and the tail attribute holds either the text between the element's end tag and the next tag, or `None`. For the XML data

        <a><b>1<c>2<d/>3</c></b>4</a>

    the a element has `None` for both text and tail attributes, the b element has text `"1"` and tail `"4"`, the c element has text `"2"` and tail `None`, and the d element has text `None` and tail `"3"`.

    To collect the inner text of an element, see `itertext()`, for example `"".join(element.itertext())`.

    Applications may store arbitrary objects in these attributes.

  `attrib`

    A dictionary containing the element's attributes. Note that while the attrib value is always a real mutable Python dictionary, an ElementTree implementation may choose to use another internal representation, and create the dictionary only if someone asks for it. To take advantage of such implementations, use the dictionary methods below whenever possible.

  Les méthodes dictionnaire-compatibles suivantes traitent les attributs de l'élément.

  `clear`()

    Resets an element. This function removes all subelements, clears all attributes, and sets the text and tail attributes to `None`.

  `get`(key, default=None)

    Accède à l'attribut de l'élément nommé key.

    Renvoie la valeur de l'attribut ou default si l'attribut n'a pas été trouvé.

  `items`()

    Renvoie les attributs de l'élément comme une séquence de paire (nom, valeur). Les attributs sont renvoyés un l'ordre arbitraire.

  `keys`()

    Returns the elements attribute names as a list. The names are returned in an arbitrary order.

  `set`(key, value)

    Change l'attribut key à l'élément value.

  Les méthodes suivantes traitent les éléments enfants (sous-éléments).

  `append`(subelement)

    Adds the element subelement to the end of this element's internal list of subelements. Raises `TypeError` if subelement is not an `Element`.

  `extend`(subelements)

    Appends subelements from a sequence object with zero or more elements. Raises `TypeError` if a subelement is not an `Element`.

    Nouveau dans la version 3.2.

  `find`(match, namespaces=None)

    Finds the first subelement matching match. match may be a tag name or a path. Returns an element instance or `None`. namespaces is an optional mapping from namespace prefix to full name. Pass `''` as prefix to move all unprefixed tag names in the expression into the given namespace.

  `findall`(match, namespaces=None)

    Finds all matching subelements, by tag name or path. Returns a list containing all matching elements in document order. namespaces is an optional mapping from namespace prefix to full name. Pass `''` as prefix to move all unprefixed tag names in the expression into the given namespace.

  `findtext`(match, default=None, namespaces=None)

    Finds text for the first subelement matching match. match may be a tag name or a path. Returns the text content of the first matching element, or default if no element was found. Note that if the matching element has no text content an empty string is returned. namespaces is an optional mapping from namespace prefix to full name. Pass `''` as prefix to move all unprefixed tag names in the expression into the given namespace.

  `getchildren`()

    Deprecated since version 3.2, will be removed in version 3.9: Use `list(elem)` or iteration.

  `getiterator`(tag=None)

    Deprecated since version 3.2, will be removed in version 3.9: Use method `Element.iter()` instead.

  `insert`(index, subelement)

    Inserts subelement at the given position in this element. Raises `TypeError` if subelement is not an `Element`.

  `iter`(tag=None)

    Creates a tree iterator with the current element as the root. The iterator iterates over this element and all elements below it, in document (depth first) order. If tag is not `None` or `'*'`, only elements whose tag equals tag are returned from the iterator. If the tree structure is modified during iteration, the result is undefined.

    Nouveau dans la version 3.2.

  `iterfind`(match, namespaces=None)

    Finds all matching subelements, by tag name or path. Returns an iterable yielding all matching elements in document order. namespaces is an optional mapping from namespace prefix to full name.

    Nouveau dans la version 3.2.

  `itertext`()

    Creates a text iterator. The iterator loops over this element and all subelements, in document order, and returns all inner text.

    Nouveau dans la version 3.2.

  `makeelement`(tag, attrib)

    Creates a new element object of the same type as this element. Do not call this method, use the `SubElement()` factory function instead.

  `remove`(subelement)

    Removes subelement from the element. Unlike the find* methods this method compares elements based on the instance identity, not on tag value or contents.

  `Element` objects also support the following sequence type methods for working with subelements: `__delitem__()`, `__getitem__()`, `__setitem__()`, `__len__()`.

  Caution: Elements with no subelements will test as `False`. This behavior will change in future versions. Use specific `len(elem)` or `elem is None` test instead.

      element = root.find('foo')

      if not element:  # careful!
          print("element not found, or element has no subelements")

      if element is None:
          print("element not found")

  Prior to Python 3.8, the serialisation order of the XML attributes of elements was artificially made predictable by sorting the attributes by their name. Based on the now guaranteed ordering of dicts, this arbitrary reordering was removed in Python 3.8 to preserve the order in which attributes were originally parsed or created by user code.

  In general, user code should try not to depend on a specific ordering of attributes, given that the XML Information Set explicitly excludes the attribute order from conveying information. Code should be prepared to deal with any ordering on input. In cases where deterministic XML output is required, e.g. for cryptographic signing or test data sets, canonical serialisation is available with the `canonicalize()` function.

  In cases where canonical output is not applicable but a specific attribute order is still desirable on output, code should aim for creating the attributes directly in the desired order, to avoid perceptual mismatches for readers of the code. In cases where this is difficult to achieve, a recipe like the following can be applied prior to serialisation to enforce an order independently from the Element creation:

      def reorder_attributes(root):
          for el in root.iter():
              attrib = el.attrib
              if len(attrib) > 1:
                  # adjust attribute order, e.g. by sorting
                  attribs = sorted(attrib.items())
                  attrib.clear()
                  attrib.update(attribs)

### Objets ElementTree

class `xml.etree.ElementTree.``ElementTree`(element=None, file=None)

  ElementTree wrapper class. This class represents an entire element hierarchy, and adds some extra support for serialization to and from standard XML.

  element is the root element. The tree is initialized with the contents of the XML file if given.

  `_setroot`(element)

    Replaces the root element for this tree. This discards the current contents of the tree, and replaces it with the given element. Use with care. element is an element instance.

  `find`(match, namespaces=None)

    Comme `Element.find()`, commence à la racine de l'arbre.

  `findall`(match, namespaces=None)

    Same as `Element.findall()`, starting at the root of the tree.

  `findtext`(match, default=None, namespaces=None)

    Same as `Element.findtext()`, starting at the root of the tree.

  `getiterator`(tag=None)

    Deprecated since version 3.2, will be removed in version 3.9: Use method `ElementTree.iter()` instead.

  `getroot`()

    Renvoie l'élément racine de l'arbre.

  `iter`(tag=None)

    Creates and returns a tree iterator for the root element. The iterator loops over all elements in this tree, in section order. tag is the tag to look for (default is to return all elements).

  `iterfind`(match, namespaces=None)

    Same as `Element.iterfind()`, starting at the root of the tree.

    Nouveau dans la version 3.2.

  `parse`(source, parser=None)

    Loads an external XML section into this element tree. source is a file name or file object. parser is an optional parser instance. If not given, the standard `XMLParser` parser is used. Returns the section root element.

  `write`(file, encoding="us-ascii", xml_declaration=None, default_namespace=None, method="xml", *, short_empty_elements=True)

    Writes the element tree to a file, as XML. file is a file name, or a file object opened for writing. encoding 1 is the output encoding (default is US-ASCII). xml_declaration controls if an XML declaration should be added to the file. Use `False` for never, `True` for always, `None` for only if not US-ASCII or UTF-8 or Unicode (default is `None`). default_namespace sets the default XML namespace (for "xmlns"). method is either `"xml"`, `"html"` or `"text"` (default is `"xml"`). The keyword-only short_empty_elements parameter controls the formatting of elements that contain no content. If `True` (the default), they are emitted as a single self-closed tag, otherwise they are emitted as a pair of start/end tags.

    The output is either a string (`str`) or binary (`bytes`). This is controlled by the encoding argument. If encoding is `"unicode"`, the output is a string; otherwise, it's binary. Note that this may conflict with the type of file if it's an open file object; make sure you do not try to write a string to a binary stream and vice versa.

    Nouveau dans la version 3.4: Le paramètre short_empty_elements.

    Modifié dans la version 3.8: The `write()` method now preserves the attribute order specified by the user.

This is the XML file that is going to be manipulated:

    <html>
        <head>
            <title>Example page</title>
        </head>
        <body>
            <p>Moved to <a href="http://example.org/">example.org</a>
            or <a href="http://example.com/">example.com</a>.</p>
        </body>
    </html>

Example of changing the attribute "target" of every link in first paragraph:

    >>> from xml.etree.ElementTree import ElementTree
    >>> tree = ElementTree()
    >>> tree.parse("index.xhtml")
    <Element 'html' at 0xb77e6fac>
    >>> p = tree.find("body/p")     # Finds first occurrence of tag p in body
    >>> p
    <Element 'p' at 0xb77ec26c>
    >>> links = list(p.iter("a"))   # Returns list of all links
    >>> links
    [<Element 'a' at 0xb77ec2ac>, <Element 'a' at 0xb77ec1cc>]
    >>> for i in links:             # Iterates through all found links
    ...     i.attrib["target"] = "blank"
    >>> tree.write("output.xhtml")

### Objets QName

class `xml.etree.ElementTree.``QName`(text_or_uri, tag=None)

  QName wrapper. This can be used to wrap a QName attribute value, in order to get proper namespace handling on output. text_or_uri is a string containing the QName value, in the form {uri}local, or, if the tag argument is given, the URI part of a QName. If tag is given, the first argument is interpreted as a URI, and this argument is interpreted as a local name. `QName` instances are opaque.

### Objets TreeBuilder

class `xml.etree.ElementTree.``TreeBuilder`(element_factory=None, *, comment_factory=None, pi_factory=None, insert_comments=False, insert_pis=False)

  Generic element structure builder. This builder converts a sequence of start, data, end, comment and pi method calls to a well-formed element structure. You can use this class to build an element structure using a custom XML parser, or a parser for some other XML-like format.

  element_factory, when given, must be a callable accepting two positional arguments: a tag and a dict of attributes. It is expected to return a new element instance.

  The comment_factory and pi_factory functions, when given, should behave like the `Comment()` and `ProcessingInstruction()` functions to create comments and processing instructions. When not given, the default factories will be used. When insert_comments and/or insert_pis is true, comments/pis will be inserted into the tree if they appear within the root element (but not outside of it).

  `close`()

    Flushes the builder buffers, and returns the toplevel document element. Returns an `Element` instance.

  `data`(data)

    Ajoute du texte à l'élément courant. data est une chaîne de caractères. Cela peut être une chaîne d'octets ou une chaîne Unicode.

  `end`(tag)

    Ferme l'élément courant. tag est le nom de l'élément. Renvoie l'élément fermé.

  `start`(tag, attrs)

    Opens a new element. tag is the element name. attrs is a dictionary containing element attributes. Returns the opened element.

  `comment`(text)

    Creates a comment with the given text. If `insert_comments` is true, this will also add it to the tree.

    Nouveau dans la version 3.8.

  `pi`(target, text)

    Creates a comment with the given target name and text. If `insert_pis` is true, this will also add it to the tree.

    Nouveau dans la version 3.8.

  In addition, a custom `TreeBuilder` object can provide the following methods:

  `doctype`(name, pubid, system)

    Handles a doctype declaration. name is the doctype name. pubid is the public identifier. system is the system identifier. This method does not exist on the default `TreeBuilder` class.

    Nouveau dans la version 3.2.

  `start_ns`(prefix, uri)

    Is called whenever the parser encounters a new namespace declaration, before the `start()` callback for the opening element that defines it. prefix is `''` for the default namespace and the declared namespace prefix name otherwise. uri is the namespace URI.

    Nouveau dans la version 3.8.

  `end_ns`(prefix)

    Is called after the `end()` callback of an element that declared a namespace prefix mapping, with the name of the prefix that went out of scope.

    Nouveau dans la version 3.8.

class `xml.etree.ElementTree.``C14NWriterTarget`(write, *, with_comments=False, strip_text=False, rewrite_prefixes=False, qname_aware_tags=None, qname_aware_attrs=None, exclude_attrs=None, exclude_tags=None)

  A C14N 2.0 writer. Arguments are the same as for the `canonicalize()` function. This class does not build a tree but translates the callback events directly into a serialised form using the write function.

  Nouveau dans la version 3.8.

### Objets XMLParser

class `xml.etree.ElementTree.``XMLParser`(*, target=None, encoding=None)

  This class is the low-level building block of the module. It uses `xml.parsers.expat` for efficient, event-based parsing of XML. It can be fed XML data incrementally with the `feed()` method, and parsing events are translated to a push API - by invoking callbacks on the target object. If target is omitted, the standard `TreeBuilder` is used. If encoding 1 is given, the value overrides the encoding specified in the XML file.

  Modifié dans la version 3.8: Parameters are now keyword-only. The html argument no longer supported.

  `close`()

    Finishes feeding data to the parser. Returns the result of calling the `close()` method of the target passed during construction; by default, this is the toplevel document element.

  `feed`(data)

    Feeds data to the parser. data is encoded data.

  `XMLParser.feed()` calls target's `start(tag, attrs_dict)` method for each opening tag, its `end(tag)` method for each closing tag, and data is processed by method `data(data)`. For further supported callback methods, see the `TreeBuilder` class. `XMLParser.close()` calls target's method `close()`. `XMLParser` can be used not only for building a tree structure. This is an example of counting the maximum depth of an XML file:

      >>> from xml.etree.ElementTree import XMLParser
      >>> class MaxDepth:                     # The target object of the parser
      ...     maxDepth = 0
      ...     depth = 0
      ...     def start(self, tag, attrib):   # Called for each opening tag.
      ...         self.depth += 1
      ...         if self.depth > self.maxDepth:
      ...             self.maxDepth = self.depth
      ...     def end(self, tag):             # Called for each closing tag.
      ...         self.depth -= 1
      ...     def data(self, data):
      ...         pass            # We do not need to do anything with data.
      ...     def close(self):    # Called when all data has been parsed.
      ...         return self.maxDepth
      ...
      >>> target = MaxDepth()
      >>> parser = XMLParser(target=target)
      >>> exampleXml = """
      ... <a>
      ...   <b>
      ...   </b>
      ...   <b>
      ...     <c>
      ...       <d>
      ...       </d>
      ...     </c>
      ...   </b>
      ... </a>"""
      >>> parser.feed(exampleXml)
      >>> parser.close()
      4

### Objets XMLPullParser

class `xml.etree.ElementTree.``XMLPullParser`(events=None)

  A pull parser suitable for non-blocking applications. Its input-side API is similar to that of `XMLParser`, but instead of pushing calls to a callback target, `XMLPullParser` collects an internal list of parsing events and lets the user read from it. events is a sequence of events to report back. The supported events are the strings `"start"`, `"end"`, `"comment"`, `"pi"`, `"start-ns"` and `"end-ns"` (the "ns" events are used to get detailed namespace information). If events is omitted, only `"end"` events are reported.

  `feed`(data)

    Feed the given bytes data to the parser.

  `close`()

    Signal the parser that the data stream is terminated. Unlike `XMLParser.close()`, this method always returns `None`. Any events not yet retrieved when the parser is closed can still be read with `read_events()`.

  `read_events`()

    Return an iterator over the events which have been encountered in the data fed to the parser. The iterator yields `(event, elem)` pairs, where event is a string representing the type of event (e.g. `"end"`) and elem is the encountered `Element` object, or other context value as follows.

    - `start`, `end`: the current Element.

    - `comment`, `pi`: the current comment / processing instruction

    - `start-ns`: a tuple `(prefix, uri)` naming the declared namespace mapping.

    - `end-ns`: `None` (this may change in a future version)

    Events provided in a previous call to `read_events()` will not be yielded again. Events are consumed from the internal queue only when they are retrieved from the iterator, so multiple readers iterating in parallel over iterators obtained from `read_events()` will have unpredictable results.

  Note

  `XMLPullParser` only guarantees that it has seen the ">" character of a starting tag when it emits a "start" event, so the attributes are defined, but the contents of the text and tail attributes are undefined at that point. The same applies to the element children; they may or may not be present.

  If you need a fully populated element, look for "end" events instead.

  Nouveau dans la version 3.4.

  Modifié dans la version 3.8: Les évènements `comment` et `pi` ont été ajoutés.

### Exceptions

class `xml.etree.ElementTree.``ParseError`

  XML parse error, raised by the various parsing methods in this module when parsing fails. The string representation of an instance of this exception will contain a user-friendly error message. In addition, it will have the following attributes available:

  `code`

    A numeric error code from the expat parser. See the documentation of `xml.parsers.expat` for the list of error codes and their meanings.

  `position`

    Un n-uplet de numéro de ligne, de colonne indiquant le lieu d'apparition de l'erreur.

Notes

1(1,2,3,4)

  La chaîne de caractères encodée inclue dans la sortie XML doit être conforme aux standards. Par exemple, « UTF-8 » est valide, mais pas « UTF8 ». Voir https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl et https://www.iana.org/assignments/character-sets/character-sets.xhtml.