When using 'w+' mode, if a file does not exist, what happens?

When using 'w+' mode in Python, if a file does not exist, it is created automatically. The 'w+' mode allows for reading and writing to a file, and if the target file is absent, the operating system will create a new file for you. This is a key feature of the 'w' mode (write), which differs from modes like 'r' (read), where attempting to read a non-existent file would result in an error.

In 'w+' mode, any existing content in the file will be truncated when opened, meaning that if the file exists, it will be overwritten. However, if it doesn’t exist, the operation simply creates it, allowing for immediate writing and reading operations once the file is opened.

This behavior is particularly useful for cases where developers wish to start fresh with a new file or ensure that they are ready to write data without having to check for the file’s prior existence.