[Tutor] search-replace

[davidheiserca at gmail.com]

Or, open the file as a blob (one long string) and do a single 'replace'.

fin = open("dirtyfile.txt", 'r').read().replace('## ', '#')
open("dirtyfile.txt", 'w').write(fin)

or,

open("dirtyfile.txt", 'w').write(open("dirtyfile.txt", 
'r').read().replace('## ', '#'))




----- Original Message ----- 
From: "Tommy Kaas" <tommy.kaas at kaasogmulvad.dk>
To: <tutor at python.org>
Sent: Monday, June 06, 2011 2:58 AM
Subject: Re: [Tutor] search-replace



> -----Oprindelig meddelelse-----
> Fra: tutor-bounces+tommy.kaas=kaasogmulvad.dk at python.org
> [mailto:tutor-bounces+tommy.kaas=kaasogmulvad.dk at python.org] På vegne
> af Alan Gauld
> Sendt: 6. juni 2011 11:51
> Til: tutor at python.org
> Emne: Re: [Tutor] search-replace
>
>
> "Tommy Kaas" <tommy.kaas at kaasogmulvad.dk> wrote
>
>
> > I'm especially interested to know how I do more than just one
> > search-replace without having to repeat the whole step below.
> > fin = open("dirtyfile.txt")
> > fout = open("cleanfile.txt", "w")
> > for line in fin:
> >    fout.write(line.replace('## ', '#'))
> > fin.close()
> > fout.close()
>
> Can be simplified to:
>
> with open("cleanfile.txt", "w") as fout:
>      for line in open("dirtyfile.txt"):
>            fout.write(line.replace('## ', '#'))
>
> To do multiple replaces simply expand the inner block
>
>
>      for line in open("dirtyfile.txt"):
>            line = line.replace(....)   #first
>            line = line.replace(....)   #second etc
>            fout.write(line)
>
> Or if you have a lot of them:
>
> replacePatterns = [('##','#'),('!!!','!!'),....]
>
>      for line in open("dirtyfile.txt"):
>             for old,new in repace_patterns:
>                  line = line.replace(old,new)
>             fout.write(line)
>


Excellent! Thanks.
tommy

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