给定字符串的正则表达式

Question

I have a small issue i am running into. I need a regular expression that would split a passed string with numbers separately and anything chunk of characters within square brackets separately and regular set of string separately.

for example if I have a strings that resembles

s = 2[abc]3[cd]ef 

i need a list with lst = ['2','abc','3','cd','ef']

I have a code so far that has this..

import re
s = "2[abc]3[cd]ef"
s_final = ""
res = re.findall("(\d+)\[([^[\]]*)\]", s)
print(res)

This is outputting a list of tuples that looks like this.

[('2', 'abc'), ('3', 'cd')]

I am very new to regular expression and learning.. Sorry if this is an easy one.

Thanks!

Answer 1

The immediate fix is getting rid of the capturing groups and using alternation to match either digits or chars other than square bracket chars:

import re
s = "2[abc]3[cd]ef"
res = re.findall(r"\d+|[^][]+", s)
print(res)
# => ['2', 'abc', '3', 'cd', 'ef']

See the regex demo and the Python demo . Details :

• \\d+ - one or more digits
• | - or
• [^][]+ - one or more chars other than [ and ]

Other solutions that might help are:

re.findall(r'\w+', s)
re.findall(r'\d+|[^\W\d_]+', s)

where \\w+ matches one or more letters, digits, underscores and some more connector punctuation with diacritics and [^\\W\\d_]+ matches any one or more Unicode letters.

See this Python demo .

Answer 2

Don't try a regex that will find all part in the string, but rather a regex that is able to match each block, and \\w (meaning [a-zA-Z0-9_] ) feats well

s = "2[abc]3[cd]ef"
print(re.findall(r"\w+", s))  # ['2', 'abc', '3', 'cd', 'ef']

Or split on brackets

print(re.split(r"[\[\]]", s))  # ['2', 'abc', '3', 'cd', 'ef ']

Answer 3

Regex is intended to be used as a Regular Expression, your string is Irregular . regex is being mostly used to find a specific pattern in a long text, text validation, extract things from text.

for example, in order to find a phone number in a string, I would use RegEx, but when I want to build a calculator and I need to extract operators/digits I would not, but I would rather want to write a python code to do that.