[Tutor] Fwd: Trying to enter text from a file to a Dictionary

[Ben Markwell]

>
>
> Hi Ben,
>
> Yes, that's the point: Python doesn't know when to stop.  *grin*
>
> The way we've rewritten the loop:
>
>     while True:
>         ...
>
> is an "infinite" loop that doesn't stop unless something in the loop's
> body does something extraordinary, like "breaking" out of the loop.
> Python is much dumber than we might expect.
>
>
> In more detail: Python's readline() method doesn't fail when we reach the
> end of a file:  we actually start hitting the empty string.  For example:
>
> ######
> >>> import StringIO
> >>> sampleTextFile = StringIO.StringIO("""This is
> ... a sample
> ... text file
> ... """)
> >>> sampleTextFile.readline()
> 'This is\n'
> >>> sampleTextFile.readline()
> 'a sample\n'
> >>> sampleTextFile.readline()
> 'text file\n'
> >>> sampleTextFile.readline()
> ''
> >>> sampleTextFile.readline()
> ''
> ######
>
> Notice that when we hit the end of the file, readline() still continues to
> run and give us empty string values.  That's why the loop above needs to
> make sure it breaks out in this particular situation.
>
>
> Does this make sense?  Please feel free to ask questions about this.
>
> Yes The  -- while true loop --  needs something to be false or it needs to
be told when to stop. If that is correct, then it makes sense.

Thanks
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