Regular Expressions 101

^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 (97₁₀) to z (122₁₀) (case sensitive)

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

Character Class[0-9a-zA-Z+.()_ ]*

*matches any number of characters from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

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

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

+the literal + (43₁₀ / 53₈ / 2B₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

(the literal ( (40₁₀ / 50₈ / 28₁₆)

)the literal ) (41₁₀ / 51₈ / 29₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

$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.

Search reference

Regular Expression

^(?=.*[a-zA-Z])[0-9a-zA-Z+.()_ ]*$

New

13221321778ok
ok2323
this(is)ok
underline_is_ok
point.isok.
this space is replaced and ok

thisandbelow+notallowed
21351
noµgood