"for line in fd" twice

Jack Diederich jack at performancedrivers.com
Tue Jun 3 17:53:47 CEST 2003


On Tue, Jun 03, 2003 at 05:24:16PM +0200, Thomas Güttler wrote:
> the following does not work:
> 
> fd=open(file)
> for line in fd:
>     if line.startswith("mymark"):
>         break
> for line in fd:
>     #Read lines after "mymark"
> 
> It works with the old way:
> 
> while 1:
>     line=fd.readline()
>     if not line:
>         break

The part
for (line) in fd:
  
will make a temporary list of all the lines in fd before it starts iterating.
so by the time you get to the second for() loop the file has been exhausted.

-jack





More information about the Python-list mailing list