Regular Expressions 101

Pro

Negative Lookbehind(?<![^\W_])

Negated Character Class[^\W_]

\Wany non-word character

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\d+a digit, repeated at least once

Positive Lookahead(?=\.\w+$)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\w+any word character, repeated at least once

$end of line

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

Detailed match information will be displayed here automatically.

25 tokens

(?<![^\W_])\d+(?=\.\w+$)

New

abc_d1.txt
abc_d1_2.txt
abc_d1_14.txt
abc_d12_3344_x2_156.txt

abc_d1.txt
abc_d1_2.txt
abc_d1_14.txt
abc_d12_3344_x2_156.txt