CODEWITHSUNDEEP
pythonregexnumbersextract
Lucian
Lucian

Reputation: 115

Python: extract numbers based on letters

I have a string ("1x5y") from which I want to extract the numbers, but I want to extract those numbers based on the letter. From my string I want to end up with x = 1 and y = 5.
Also, either x or y may or may not be present in the string, but at least one of them will always be present (and only once, not more than once).
I managed to do this with regex and a few "if"s, but I was wondering if there is a more elegant solution.

Thank you

EDIT: here is what I have

delta = "2y"
if ("x" in delta) and ("y" in delta):
    x = re.findall('\d+',str(re.findall('\d+x',delta)))
    y = re.findall('\d+',str(re.findall('\d+y',delta)))
elif ("x" in delta) and ("y" not in delta):
    x = re.findall('\d+',str(re.findall('\d+x',delta)))
elif ("x" not in delta) and ("y" in delta):
    y = re.findall('\d+',str(re.findall('\d+y',delta)))
else:
    x = y = 0

Upvotes: 0

Views: 102

Answers (2)

DeepSpace
DeepSpace

Reputation: 81604

The most basic and naive regex to solve this is (\d+)([a-zA-Z]), and there's no need for any ifs. The capturing groups will take care for "associating" each number to the letter on the right of it.

import re

regex = re.compile(r'(\d+)([a-zA-Z])')
for string in ['1x5y', '1x', '5y', '111x2y333z']:
    print(string)
    for number, letter in regex.findall(string):
        print(number, letter)
    print()

Outputs

1x5y
1 x
5 y

1x
1 x

5y
5 y

111x2y333z
111 x
2 y
333 z

Upvotes: 1

Conner
Conner

Reputation: 31060

You can precompile the regex and assign with findall() 

import re

s = "1x5y"
p = re.compile(r'(\d+)x(\d+)y')
(x, y) = re.findall(p, s)[0]

Upvotes: 0

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