Looping through python regex matches

Question

I want to turn a string that looks like this:

ABC12DEF3G56HIJ7

into

12 * ABC
3  * DEF
56 * G
7  * HIJ

I want to construct the correct set of loops using regex matching. The crux of the issue is that the code has to be completely general because I cannot assume how long the [A-Z] fragments will be, nor how long the [0-9] fragments will be.

Asked By: da5id

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Source

Answer 1

Python’s re.findall should work for you.

Live demo

import re

s = "ABC12DEF3G56HIJ7"
pattern = re.compile(r'([A-Z]+)([0-9]+)')

for (letters, numbers) in re.findall(pattern, s):
    print(numbers, '*', letters)

Answered By: Ray Toal

Answer 2

It is better to use re.finditer if your dataset is large because that reduces memory consumption (findall() return a list of all results, finditer() finds them one by one).

import re

s = "ABC12DEF3G56HIJ7"
pattern = re.compile(r'([A-Z]+)([0-9]+)')

for m in re.finditer(pattern, s):
    print m.group(2), '*', m.group(1)

Answered By: Mithril

Answer 3

Yet another option could be to use re.sub() to create the desired strings from the captured groups:

import re
s = 'ABC12DEF3G56HIJ7'
for x in re.sub(r"([A-Z]+)(d+)", r'2 * 1,', s).rstrip(',').split(','):
    print(x)

12 * ABC
3 * DEF
56 * G
7 * HIJ

Answered By: cottontail

Looping through python regex matches

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