LinuxQuestions.org - Extracting a Number from a String

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- - Extracting a Number from a String (https://www.linuxquestions.org/questions/programming-9/extracting-a-number-from-a-string-728542/)

nilly16

05-26-2009 04:29 AM

Extracting a Number from a String

Quote:

The Angels,Take A Long Line,180,

How do I take this string of text & extract & store the number 180 in an array?

What functions do I use? For example cin.ignore(array, ",")

I have a whole text file where I have to extract just the numbers from each string.

Quote:

Alison Moyet,All Cried Out,410,
Allan Browne Quintet,Cyclosporin,291,
The Angels,Take A Long Line,180,
Architecture In Helsinki,Maybe You Can Owe Me,242,

Sergei Steshenko

05-26-2009 04:44 AM

Quote:

Originally Posted by nilly16 (Post 3552907)

What computer programming language are you talking about ?

ghostdog74

05-26-2009 05:26 AM

most probably C++
@OP, i assume you are not doing homework and are free to use any programming language you might have

Code:

# awk -F"," '{print $(NF-1)}' file

410

291

180

242

if you have Python

Code:

# python -c "print '\n'.join([i.strip().split(',')[-2] for i in open('file')])"

410

291

180

242

Sergei Steshenko

05-26-2009 06:09 AM

Quote:

Originally Posted by ghostdog74 (Post 3552958)

most probably C++
@OP, i assume you are not doing homework and are free to use any programming language you might have

Code:

# awk -F"," '{print $(NF-1)}' file

410

291

180

242

if you have Python

Code:

# python -c "print '\n'.join([i.strip().split(',')[-2] for i in open('file')])"

410

291

180

242

Huh ?

Code:

echo 'Alison Moyet,All Cried Out,410' | perl -e '$_=<STDIN>;m/(\d+)/; print $1, "\n"'

410

syg00

05-26-2009 06:16 AM

Much as I appreciate perl, this just screams for grep.
Now, if there are an indeterminate number of digit (sub)strings, that might change my leaning.

Sergei Steshenko

05-26-2009 06:17 AM

Quote:

Originally Posted by syg00 (Post 3552995)

Much as I appreciate perl, this just screams for grep.
Now, if there are an indeterminate number of digit (sub)strings, that might change my leaning.

Does 'grep' extract numbers ? I think it just matches, and the OP needs extraction.

ghostdog74

05-26-2009 06:19 AM

Quote:

Originally Posted by Sergei Steshenko (Post 3552988)

Huh ?

what?

syg00

05-26-2009 06:21 AM

echo 'Alison Moyet,All Cried Out,410' | grep -Eo "[[:digit:]]*"
410

ghostdog74

05-26-2009 06:23 AM

note that sample data has ending ","

colucix

05-26-2009 06:25 AM

Shell:

Code:

string="The Angels,Take A Long Line,180,"

string=${string%,}

number=${string##*,}

syg00

05-26-2009 06:28 AM

Quote:

Originally Posted by ghostdog74 (Post 3553004)

note that sample data has ending ","

So ???.
Try this

Code:

echo 'Alison Moyet,All Cried Out,410,ad,333,' | grep -Eo "[[:digit:]]*"

Sergei Steshenko

05-26-2009 06:29 AM

Quote:

Originally Posted by ghostdog74 (Post 3552998)

what?

Too much complexity in your Python code.

ghostdog74

05-26-2009 06:31 AM

Quote:

Originally Posted by syg00 (Post 3553011)

So ???.
Try this

Code:

echo 'Alison Moyet,All Cried Out,410,ad,333,' | grep -Eo "[[:digit:]]*"

Code:

# echo 'Alison Moyet,All Cried Out,410,ad,333,' | grep -Eo "[[:digit:]]+"

410

333

ghostdog74

05-26-2009 06:38 AM

Quote:

Originally Posted by Sergei Steshenko (Post 3553012)

Too much complexity in your Python code.

Code:

#!/usr/bin/env python

for line in open('file')

    print line.strip().split(',')[-2]

(NB. "complexity" is subjective)

pixellany

05-26-2009 06:38 AM

nilly;

This thread is your third one on what appears to be the same homework assignment. These threads should have been kept together---or at least you should have referenced them. It's a little late, but I've included the canned response for homework threads.

Quote:

Per the LQ Rules, please do not post homework assignments verbatim. We're happy to assist if you have specific questions or have hit a stumbling point, however. Let us know what you've already tried and what references you have used (including class notes, books, and Google searches) and we'll do our best to help. Also, keep in mind that your instructor might also be an LQ member.

I'm reporting all of your threads for closure.

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