seafoid wrote:
> Hi Guys,
>
> When python reads in a file, can lines be referred to via an index?
>
> Example:
>
> for line in file:
> if line[0] == '0':
> a.write(line)
>
> This works, however, I am unsure if line[0] refers only to the first line or
> the first character in all lines.
>
> Is there an easy way to refer to a line with the first character being a
> single letter that you know?
>
> Thanks in advance,
> Seafoid.
If you want to know the index number of an item in a sequence you are
looping through (whether it be a file of lines or a list of characters,
whatever) use enumerate...
>>> for index, value in enumerate("ABCD"):
print index, value
...
0 A
1 B
2 C
3 D
If you want to extract an index number from the first part of of a given
line use split( split_character, maximum_splits_to_do ) and then angle
brackets to reference the first part (index 0)...
>>> a = "20 GOTO 10"
>>> int( a.split(' ',1)[0] )
20
Cheers,
Roger.
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