Excel file in use from Python

[deanhystad]

This creates a context where the file is open.

with open(filename, 'w') as file:
    file.write('text')

The file only remains open while in this context. The context ends when you leave the code block. You leave the code block when you de-indent.

def func(arg):
    # Assumes caller's context.  So file still open.
    pass

with open(filename, 'w') as file:
    file.write('text')
    # File is still open
    func(file)  # Called function executes in current context.
    # File is still open
# De-indent ends block of code.  File is closed

If you have a lot of code that must execute with the file open I would put that code inside a function and call the function from inside the context manager as shown above.