[Tutor] Regular expression re.search() object . Please help

[Jacob S.]

I assume that both you and Liam are using previous-er versions of python?
Now files are iterators by line and you can do this.

openFile = open("probe_pairs.txt","r")
indexesToRemove = []
for line in openFile:
    if line.startswith("Name="):
        line = ''   ## Ooops, this won't work because it just changes what
line references or points to or whatever, it doesn't
                    ##actually change the object
openFile.close()

I think this is a great flaw with using for element in list instead of for
index in range(len(list))

Of course you later put IMHO better solutions (list comprehensions,etc.) -- 
I just wanted to point out that files have been
iterators for a few versions now and that is being used more and more. It
also saves the memory problem of using big files
and reading them all at once with readlines.

Jacob

> Liam Clarke wrote:
>
> > openFile=file("probe_pairs.txt","r")
> > probe_pairs=openFile.readlines()
> >
> > openFile.close()
> >
> > indexesToRemove=[]
> >
> > for lineIndex in range(len(probe_pairs)):
> >
> >        if probe_pairs[lineIndex].startswith("Name="):
> >                      probe_pairs[lineIndex]=''
>
> If the intent is simply to remove all lines that begin with "Name=",
> and setting those lines to an empty string is just shorthand for that,
> it'd make more sense to do this with a filtering list comprehension:
>
>      openfile = open("probe_pairs.txt","r")
>      probe_pairs = openfile.readlines()
>      openfile.close()
>
>      probe_pairs = [line for line in probe_pairs \
>                            if not line.startswith('Name=')]
>
>
> (The '\' line continuation isn't strictly necessary, because the open
> list-comp will do the same thing, but I'm including it for
> readability's sake.)
>
> If one wants to avoid list comprehensions, you could instead do:
>
>      openfile = open("probe_pairs.txt","r")
>      probe_pairs = []
>
>      for line in openfile.readlines():
>          if not line.startswith('Name='):
>              probe_pairs.append(line)
>
>      openfile.close()
>
> Either way, lines that start with 'Name=' get thrown away, and all
> other lines get kept.
>
> Jeff Shannon
> Technician/Programmer
> Credit International
>
>
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