Python file handling - writing

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See [[Python file handling - reading]]

For code examples see [[Week4 Writing to Files Lab]]

Using 'w' mode

This time we use w for write mode.

with open("/resources/data/Example2.txt", "w") as File1:
	File1.write("This is line A")

This will write This is line A to the first line of the file, overwriting whatever was there before.

Successive calls of .write() will write to a new line in the file.

Using 'a' mode

Using a mode will append lines to the end of an existing file.

It is also common to use for loops to add list or dictionary elements to a file.

with open("/resources/data/Example2.txt", "a") as File1:
	for item in source_list:
		File1.write(item)

Nesting files

You can nest file context managers to perform functions such as copying the contents of one file to another. See the graphic below.