[Tutor] Regular Expression help

[Gardner, Dean]

Thanks everyone for the replies all worked well, I adopted the string
splitting approach in favour of the regex one as it seemed to miss less
of the edge cases. I would like to thank everyone for their help once
again 




-----Original Message-----
From: Kent Johnson [mailto:kent37 at tds.net] 
Sent: 27 June 2007 14:55
To: tutor at python.org; Gardner, Dean
Subject: Re: [Tutor] Regular Expression help

Gardner, Dean wrote:
> Hi
> 
> I have a text file that I would like to split up so that I can use it 
> in Excel to filter a certain field. However as it is a flat text file 
> I need to do some processing on it so that Excel can correctly import
it.
> 
> File Example:
> tag             desc                    VR      VM
> (0012,0042) Clinical Trial Subject Reading ID LO 1
> (0012,0050) Clinical Trial Time Point ID LO 1
> (0012,0051) Clinical Trial Time Point Description ST 1
> (0012,0060) Clinical Trial Coordinating Center Name LO 1
> (0018,0010) Contrast/Bolus Agent LO 1
> (0018,0012) Contrast/Bolus Agent Sequence SQ 1
> (0018,0014) Contrast/Bolus Administration Route Sequence SQ 1
> (0018,0015) Body Part Examined CS 1
> 
> What I essentially want is to use python to process this file to give 
> me
> 
> 
> (0012,0042); Clinical Trial Subject Reading ID; LO; 1 (0012,0050); 
> Clinical Trial Time Point ID; LO; 1 (0012,0051); Clinical Trial Time 
> Point Description; ST; 1 (0012,0060); Clinical Trial Coordinating 
> Center Name; LO; 1 (0018,0010); Contrast/Bolus Agent; LO; 1 
> (0018,0012); Contrast/Bolus Agent Sequence; SQ ;1 (0018,0014); 
> Contrast/Bolus Administration Route Sequence; SQ; 1 (0018,0015); Body 
> Part Examined; CS; 1
> 
> so that I can import to excel using a delimiter.
> 
> This file is extremely long and all I essentially want to do is to 
> break it into it 'fields'
> 
> Now I suspect that regular expressions are the way to go but I have 
> only basic experience of using these and I have no idea what I should
be doing.

This seems to work:

data = '''\
(0012,0042) Clinical Trial Subject Reading ID LO 1
(0012,0050) Clinical Trial Time Point ID LO 1
(0012,0051) Clinical Trial Time Point Description ST 1
(0012,0060) Clinical Trial Coordinating Center Name LO 1
(0018,0010) Contrast/Bolus Agent LO 1
(0018,0012) Contrast/Bolus Agent Sequence SQ 1
(0018,0014) Contrast/Bolus Administration Route Sequence SQ 1
(0018,0015) Body Part Examined CS 1'''.splitlines()

import re
fieldsRe = re.compile(r'^(\(\d+,\d+\)) (.*?) (\w+) (\d+)$')

for line in data:
    match = fieldsRe.match(line)
    if match:
        print ';'.join(match.group(1, 2, 3, 4))


I don't think you want the space after the ; that you put in your
example; Excel wants a single-character delimiter.

Kent


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