Regular Expressions 101

^start of line

Negative Lookahead(?!.*([.,']).*\1)

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

Group 1([.,'])

Character Class[.,']

.the literal . (46₁₀ / 56₈ / 2E₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

'the literal ' (39₁₀ / 47₈ / 27₁₆)

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

\1the text saved by group 1

Character Class[a-zA-Z.,']*

*matches any number of characters from the set below:

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

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

.the literal . (46₁₀ / 56₈ / 2E₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

'the literal ' (39₁₀ / 47₈ / 27₁₆)

$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

^(?!.*([.,']).*\1)[a-zA-Z.,']*$

New

String.,'
y.yy
.bb,b
y,yyy.
.b'bb
bbb'
a,y.

a,z,f
y.t.e