Regular Expressions 101

^start of line

Negative Lookahead(?!.*(\d)\1{3})

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

Group 1(\d)

\da digit

\1{3}the text saved by group 1, repeated exactly 3 times

Character Class[03]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Negative Lookahead(?!\d*(?:0123|1234|2345|3456|4567|5678|6789))

\d*a digit, repeated any number of times

Non-Capturing Group(?:0123|1234|2345|3456|4567|5678|6789)

1st Alternative0123

0123the literal text 0123

2nd Alternative1234

1234the literal text 1234

3rd Alternative2345

2345the literal text 2345

4th Alternative3456

3456the literal text 3456

5th Alternative4567

4567the literal text 4567

6th Alternative5678

5678the literal text 5678

7th Alternative6789

6789the literal text 6789

\d{6,10}a digit, repeated between 6 and 10 times

$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

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Search reference

Regular Expression

^(?!.*(\d)\1{3})[03](?!\d*(?:0123|1234|2345|3456|4567|5678|6789))\d{6,10}$

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