Regular Expressions 101

Explanation
Pro

^start of line

Positive Lookahead(?=.*[A-Za-z])

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

Character Class[A-Za-z]

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

\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

^(?=.*[A-Za-z])\w+$

123
_123
123_
a_123
a12_3
asd
as_j
a_

123
_123
123_
a_123
a12_3
asd
as_j
a_