regex101: PCRE (Legacy) Match Workspace

\ban ASCII word boundary

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

Group 1(\d)

\da digit

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

Character Class[13-9]{4}

{4}matches exactly 4 characters from the set below:

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3-9one character from 3 (51₁₀) to 9 (57₁₀)

Character Class[1346-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

6-9one character from 6 (54₁₀) to 9 (57₁₀)

Character Class[013-9]{5}

{5}matches exactly 5 characters from the set below:

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3-9one character from 3 (51₁₀) to 9 (57₁₀)

\ban ASCII word boundary

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

25 tokens

Regular Expression

\b(?!(\d)\1{3})[13-9]{4}[1346-9][013-9]{5}\b

New

1345678939 all not same; 1st 4 not same, 5th digit not 5, all digits
3333333333 all are same
4444151617 1st 4 are same
3167518888 5th digit = 5
9876877772 contains a 2
9876870773 contains a 0 in last 5 digits
9870677665 contains a 0 in first 5 digits

Extraction

1345678939 all not same; 1st 4 not same, 5th digit not 5, all digits
3333333333 all are same
4444151617 1st 4 are same
3167518888 5th digit = 5
9876877772 contains a 2
9876870773 contains a 0 in last 5 digits
9870677665 contains a 0 in first 5 digits