Regex in Python to get string of numbers after string of letters

Question

I have a string formatted as results_item12345. The numeric part is either four or five digits long. The letters will always be lowercase and there will always be an underscore somewhere in the non-numeric part.

I tried to extract it using the following:

 import re
 string = 'results_item12345'
 re.search(r'[^a-z][\d]',string)

However, I only get the leftmost two digits. How can I get the entire number?

Your regex is currently matching "a single character that is not a-z followed by a single digit". That should shed some light on what is happening. — Randy Morris
– Randy Morris, Commented Oct 11, 2012 at 19:11

Jason McCreary · Accepted Answer · 2012-10-11 19:16:27Z

7

Assuming you only care about the numbers at the end of the string, the following expression matches 4 or 5 digits at the end of the string.

\d{4,5}$

Otherwise, the following would be the full regex matching the provided requirements.

^[a-z_]+\d{4,5}$

edited Oct 11, 2012 at 19:16

answered Oct 11, 2012 at 19:11

Jason McCreary

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2 Comments

GaretJax Over a year ago

Its backslash, but that's the solution ;)

GaretJax Over a year ago

Yep, saw that… one second after hitting the button

Vyktor · Accepted Answer · 2012-10-11 19:31:05Z

2

If you wanted to just match any number in the string you could search for:

r'[\d]{4,5}'

If you need validation of some sort you need to use:

r'^result_item[\d]{4,5}$'

edited Oct 11, 2012 at 19:31

answered Oct 11, 2012 at 19:13

Vyktor

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2 Comments

Vyktor Over a year ago

@JasonMcCreary updated it just before you posted comment... Thanks anyway.

Vyktor Over a year ago

@JasonMcCreary thanks, I know that but I prefer to always encapsulate character groups into braces, it's easier for me to read :)

vks · Accepted Answer · 2014-05-27 11:12:32Z

1

import re    
a="results_item12345"
pattern=re.compile(r"(\D+)(\d+)")
x=pattern.match(a).groups()
print x[1]

answered May 27, 2014 at 11:12

vks

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