Question on `print f.read()` behavior

[pythonjohn]

Say I open a file using

lookingatfile = open([i]filename[/i])

when I then type

print lookingatfile.read()

the contents of the file are output.

However, if I open a file using

lookingatfile = open([i]filename[/i])

and then I type
x = lookingatfile.read()

nothing is output to the screen when I type print lookingatfile.read() and I only get text output to the screen when type print x

Why does print lookingatfile.read() print nothing, once I've assigned it to a variable in the script (eg, using x = lookingatfile.read())?

[micseydel]

You could have that succeed if right before that you use lookingatfile.seek(0). Basically, when you read from a file a "pointer" is advanced from position 0, and that position is saved. If you read the whole file, then you're at the end, and when it tries to read it again it finds there's nothing left. Usually we don't read from a file manually, we iterate over the lines in a file, and this behavior that you might find confusing is actually consistent with that use case as well as how files are often read manually (as in the C programming language).

[pythonjohn]

Ah - thanks. That explains it