do a sed / awk filter with python tools (at least as fast)


M

Mathieu Prevot

Hi,

I use in a bourne shell script the following filter:

sed '/watch?v=/! d;s/.*v=//;s/\(.\{11\}\).*/\1/' \
| sort | uniq | awk 'ORS=" "{print $1}'

that give me all sets of 11 characters that follows the "watch?v="
motif. I would like to do it in python on stdout from a
subprocess.Popen instance, using python tools rather than sed awk etc.
How can I do this ? Can I expect something as fast ?

Thanks,
Mathieu
 
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P

Peter Otten

Mathieu said:
I use in a bourne shell script the following filter:

sed '/watch?v=/! d;s/.*v=//;s/\(.\{11\}\).*/\1/' \
| sort | uniq | awk 'ORS=" "{print $1}'

that give me all sets of 11 characters that follows the "watch?v="
motif. I would like to do it in python on stdout from a
subprocess.Popen instance, using python tools rather than sed awk etc.
How can I do this ? Can I expect something as fast ?

You should either do it in Python , e. g.:

def process(lines):
candidates = (line.rstrip().partition("/watch?v=") for line in lines)
matches = (c[:11] for a, b, c in candidates if len(c) >= 11)
print " ".join(sorted(set(matches)))

if __name__ == "__main__":
import sys
process(sys.stdin)

or invoke your shell script via subprocess.Popen(). Invoking a python script
via subprocess doesn't make sense IMHO.

Peter
 
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M

Mathieu Prevot

2008/7/7 Peter Otten said:
Mathieu said:
I use in a bourne shell script the following filter:

sed '/watch?v=/! d;s/.*v=//;s/\(.\{11\}\).*/\1/' \
| sort | uniq | awk 'ORS=" "{print $1}'

that give me all sets of 11 characters that follows the "watch?v="
motif. I would like to do it in python on stdout from a
subprocess.Popen instance, using python tools rather than sed awk etc.
How can I do this ? Can I expect something as fast ?

You should either do it in Python , e. g.:

def process(lines):
candidates = (line.rstrip().partition("/watch?v=") for line in lines)
matches = (c[:11] for a, b, c in candidates if len(c) >= 11)
print " ".join(sorted(set(matches)))

if __name__ == "__main__":
import sys
process(sys.stdin)

or invoke your shell script via subprocess.Popen(). Invoking a python script
via subprocess doesn't make sense IMHO.

:) Thanks.
Mathieu
 

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