# Python XML Processing (ElementTree)

XML (eXtensible Markup Language) is a markup language similar to HTML, but without predefined tags. Python's `xml.etree.ElementTree` module provides a simple and efficient API for parsing and creating XML data.

## Importing the Module

```python
import xml.etree.ElementTree as ET
```

## Parsing XML

### From a String

```python
import xml.etree.ElementTree as ET

data = """
<data>
    <country name="Liechtenstein">
        <rank>1</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
</data>
"""

root = ET.fromstring(data)
print(root.tag) # Output: data
```

### From a File

```python
import xml.etree.ElementTree as ET

# Assuming 'country_data.xml' exists
# tree = ET.parse('country_data.xml')
# root = tree.getroot()
```

## Accessing Elements

You can access child elements by index or iterate over them.

```python
# Accessing child by index
country = root[0]
rank = country.find('rank').text
print(rank) # Output: 1
```

Attributes are accessed as a dictionary.

```python
print(root[0].attrib)
# Output: {'name': 'Liechtenstein'}
```

## Finding Elements

### `find()`

Returns the first matching element.

```python
rank = root.find(".//rank")
print(rank.text)
```

### `findall()`

Returns a list of all matching elements.

```python
for neighbor in root.iter('neighbor'):
    print(neighbor.attrib)
```

## Modifying XML

You can modify text, attributes, and tags directly.

```python
for rank in root.iter('rank'):
    new_rank = int(rank.text) + 1
    rank.text = str(new_rank)
    rank.set('updated', 'yes')
```

## Creating XML

You can create XML trees from scratch.

```python
import xml.etree.ElementTree as ET

a = ET.Element('a')
b = ET.SubElement(a, 'b')
c = ET.SubElement(a, 'c')
c.text = 'Some text'

print(ET.tostring(a, encoding='unicode'))
# Output: <a><b /><c>Some text</c></a>
```

[[programming/python/python]]