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open and close

Open your file in write mode

When you use the open() BIF to work with a disk file, you can specify an
access mode to use. By default, open() uses mode r for reading, so you don’t
need to specify it. To open a file for writing, use mode w: The access model
to use

The data file out = open("data.out", "w")
object
The name of the file to
write to

By default, the print() BIF uses standard output (usually the screen) when
displaying data. To write data to a file instead, use the file argument to
specify the data file object to use:

print("Norwegian Blues stun easily.", file=out)

The name of the data
What gets written to the file
file object to write to
When you’re done, be sure to close the file to ensure all of your data is written
to disk. This is known as flushing and is very important:

This is VERY important
out.close() when writing to files.

Geek Bits

When you use access mode w, Python opens your named file
for writing. If the file already exists, it is cleared of its contents, or
clobbered. To append to a file, use access mode a, and to open a
file for writing and reading (without clobbering), use w+. If you
try to open a file for writing that does not already exist, it is first
created for you, and then opened for writing.

110 Chapter 4