regex101: Python Match Workspace

Pro

Positive Lookahead(?=^(?:(?!key[12]).)*$)

^start of line

Non-Capturing Group(?:(?!key[12]).)*

*repeats the group contents below any number of times:

Negative Lookahead(?!key[12])

keythe literal text key (case sensitive)

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

.any Unicode character (except for line terminators)

$end of line

^start of line

.*?any Unicode character (except for line terminators), repeated any number of times

Positive Lookahead(?=\s\d+)

\sa Unicode whitespace character

\d+a Unicode decimal digit, repeated at least once

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

25 tokens

Regular Expression

(?=^(?:(?!key[12]).)*$)^.*?(?=\s\d+)

New

this is a number 123456789 and there aren't any keys here. we might have a lot of words here as well but no key words
this is a number 123456789 but we have their key1 here. key2 might be in the second or the third sentence. hence we can't remove everything after the given number

Substitution

this is a number 123456789 and there aren't any keys here. we might have a lot of words here as well but no key words
this is a number 123456789 but we have their key1 here. key2 might be in the second or the third sentence. hence we can't remove everything after the given number