[python] How to read a file line-by-line into a list?

You could simply do the following, as has been suggested:

with open('/your/path/file') as f:
    my_lines = f.readlines()

Note that this approach has 2 downsides:

1) You store all the lines in memory. In the general case, this is a very bad idea. The file could be very large, and you could run out of memory. Even if it's not large, it is simply a waste of memory.

2) This does not allow processing of each line as you read them. So if you process your lines after this, it is not efficient (requires two passes rather than one).

A better approach for the general case would be the following:

with open('/your/path/file') as f:
    for line in f:
        process(line)

Where you define your process function any way you want. For example:

def process(line):
    if 'save the world' in line.lower():
         superman.save_the_world()

(The implementation of the Superman class is left as an exercise for you).

This will work nicely for any file size and you go through your file in just 1 pass. This is typically how generic parsers will work.

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