how to count lines in a file ?

[Chris Liechti]

"Shagshag13" <shagshag13 at yahoo.fr> wrote in news:ahk3la$tf3bh$1 at ID-
146704.news.dfncis.de:

> here is a test in counting [6871785] lines from a file of > 1Go
> 
> ---
> lineCount = 0
> fhi = file(filename)
> for line in xreadlines.xreadlines(fhi):

note that a fileobject has an xreadlines method. no need to use the module

>  lineCount += 1
> 
> return lineCount
> 
>  [Eof processing] : 00:01:22
> ---
> lines = 0:
> for line in file(filename):
>      lines += 1
> 
>  [Eof processing] : 00:01:22

it's not a coincidence that the times are equal as iterating through a file 
with "for line in file()" is just a shortcut for "for line in 
file().xreadlines()"

> ---
> lineCount = 0
> fp = open(filename)
> it = iter(fp)
> try:
>  while it.next():
>   lineCount += 1
> except StopIteration:
>  pass
> 
> return lineCount
> 
>  [Eof processing] : 00:01:42

as I just meantioned in an other message, that's just handcoding of "for 
line in file()" and ignoring the "line" variable.
it is slower because the call to next is done in python, whereas the "for" 
solution does this internally (in C).

all code you show is basicaly the same. the middle solution is the most 
readble in my opinion.

chris

-- 
Chris <cliechti at gmx.net>