Python ElementTree tostring write()

ElementTree is a Python library used for parsing and manipulating XML data. The tostring function is used to convert an ElementTree element to a string representation. However, it requires the parameter to be a string and not bytes.

Issue Description

When using the tostring function from the ElementTree module in Python, it is important to note that the parameter passed to the function must be a string. Passing a byte object will result in a TypeError being raised.

Solution

To solve this issue, you need to ensure that the parameter passed to the tostring function is of the correct type, i.e., a string.

One common mistake is reading an XML file in binary mode using open() and passing the file object directly to ElementTree.parse(). In this case, the resulting element will contain binary data. To convert it to a string, you need to call the .decode() method on the binary data.

Here's an example that demonstrates the correct usage:

import xml.etree.ElementTree as ET

# Read XML file in binary mode
with open("example.xml", "rb") as f:
    tree = ET.parse(f)

root = tree.getroot()

# Convert the element to a string
xml_string = ET.tostring(root, encoding="utf-8").decode("utf-8")

# Write the string to a file
with open("output.xml", "w") as f:
    f.write(xml_string)

In the above example, the XML file "example.xml" is read in binary mode, and the resulting element is converted to a string representation using tostring with encoding="utf-8". Then, the string is written to a file "output.xml" using the write function.

Make sure to specify the correct encoding when converting the element to a string and also when writing it to a file.

By following this approach, you can ensure that the tostring function works correctly without raising a TypeError related to passing bytes instead of a string.

Remember, always read the ElementTree documentation and check the types of parameters accepted by the functions to avoid such errors.