reading and writing files in Python


Here are several references

Opening and Closing Files

The simplest code to open an input file looks like this (see p. 109 in Perkovic 2nd edition)

infile = open('example.txt', 'r')

If you do it this way, you have the obligation to later close the file, like this, when you are finished with it:


A way that may Python programmers prefer is to use a with statement, like this:

  with open('example.txt','r') as infile:
     data =

With this style of coding, all the code you want to do while the file is open is done inside the indented with block. The file infile is automatically closed as soon as the indented block is exited.

Reading from a file

Read the whole file at once

This code reads the entire contents of the file into the variable data.

  with open('example.txt','r') as infile:
     data =

If you want to treat the different lines of the file as separate lines after that, you could use this code to convert data to a list of strings called lines, one per line:

  lines = data.split("\n")

That’s only a good idea if the file is relatively small.