I've been facing this problem that I cannot solve.

compiler = re.compile(r'\d*[05]')
result = compiler.findall('0 20 201 95 5 52 35 999 40 19 50 1000 245 1050 118 2500')

Desired output: ['20', '95', '5', '35', '40', '50', '1000', '245']

The closest that I can achieve, based on my code above: ['0', '20', '20', '95', '5', '5', '35', '40', '50', '1000', '245', '1050', '2500']

I am supposed to provide my answer in only the dashed portion of the code re.compile(r'--------').

If someone can help me out that'll be great, thanks.

CodePudding user response：

As pointed out by @depperm

\b(?!\b0\b)(\d{0,2}[05]|1000)\b

would be the perfect regex for your demand.

My idea just works for a single number

^\d{0,2}[05]$|^1000$

Explanation:

• ^ shows, that the string has to start here
• /d{0,2} stands for 0,1 or 2 numbers
• [05] the number 0 or 5 because the all multiples of 5 end with 0 or 5
• $ end of the string
• | stands for the operator or
• ^1000$ stands for the string 1000

but as already pointed out you could look in too other ways as well

CodePudding user response：

You don't need to use regex for this. You can use a comprehension:

result = [i for i in data.split() if not (n := int(i)) % 5 and n <= 1000 and n]

This is equivalent to:

result = []
for i in data.split():
    n = int(i)
    if not n % 5 and n <= 1000 and n:
        result.append(i)

CodePudding user response：

When it's all in one string, we need to add boundaries to our search. Another answer was close, but we can't match by ^ and $ when the single string contains multiple values.

\b or word boundaries makes sure that there aren't additional digits before or after a matching string.

Pattern: \b0\b|(\b\d{0,2}[05]\b|\b1000\b)

All the desired matches are in group 1

https://regex101.com/r/Efhcsb/2

CodePudding user response：

The requirement can be met by using the regex pattern, (\b(?=[^0])\d{0,2}[05])\b|1000.

Demo:

import re

compiler = re.compile(r'(?:\b(?=[^0])\d{0,2}[05])\b|1000')
result = compiler.findall('0 20 201 95 5 52 35 999 40 19 50 1000 245 1050 118 2500')
print(result)

Output:

['20', '95', '5', '35', '40', '50', '1000', '245']

Explanation of the regex:

• (?: : Start of non-capturing group
  • \b: Word boundary
  • (?=[^0]) : Positive lookahead asserting that there should not be 0 ahead of the current postion
  • \d{0,2} : A digit zero to two times
  • [05] : 0 or 5
• ) : End of non-capturing group
• |1000 : OR 1000