python: create raw string of variables

Question

i have to read a line in which i looking for pattern like

width:40
height :50
left : 60
right: 70

following found the required pattern

line = "width:40"
match = re.search(r'width\s*:\s*\d+', line)

in above code i have hard-coded the regex pattern for width

i have stored all four variables in array key_word = ['width', 'height', 'left', 'right']

i want to search for pattern for all these variable like

for key in key_word:
        match = re.search(key, line)

the problem is how can i make this key a raw string which will be a pattern like

r'width\s*:\s*\d+'
r'height\s*:\s*\d+'
r'left\s*:\s*\d+'
r'right\s*:\s*\d+'

Andrew Clark · Accepted Answer · 2013-03-28 17:54:28Z

2

I would do something like the following:

key_word = ['width', 'height', 'left', 'right']
regex_template = r'{}\s*:\s*\d+'
for key in key_word:
    print re.search(regex_template.format(key), line)

answered Mar 28, 2013 at 17:54

Andrew Clark

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Blender · Accepted Answer · 2013-03-28 17:55:44Z

1

You can also just use a generic regex:

matches = re.findall(r'(.*?)\s*:\s*(\d+)', text)

matches will be a list of (key, value) tuples.

answered Mar 28, 2013 at 17:55

Blender

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Dan Lecocq · Accepted Answer · 2013-03-28 17:51:36Z

0

Why not use split (or partition) and strip?

for line in lines:
    key, sep, value = line.partition(':')
    key = key.strip()
    value = value.strip()

If you're really needing to use regular expressions, you can format them, too:

r'%s\s*:\s*\d+' % 'width'

Or for each key:

regexes = [r'%s\s*:\s*\d+' % key for key in ['width', 'height', ...]]

answered Mar 28, 2013 at 17:51

Dan Lecocq

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Francis Avila · Accepted Answer · 2013-03-28 18:00:51Z

0

You don't need regular expressions for this task. See other answers.

However if you insist, you can create one dynamically using re.escape:

import re

key_word = ['width', 'height', 'left', 'right']

myre = r'({})\s*:\s*(\d+)'.format('|'.join(map(re.escape, key_word)))

answered Mar 28, 2013 at 18:00

Francis Avila

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