Regular Expressions 101

^start of string

Positive Lookahead(?=(?!([0-9])\1{2}[-. ]*\1{3}[-. ]*\1{4}$))

Negative Lookahead(?!([0-9])\1{2}[-. ]*\1{3}[-. ]*\1{4}$)

Group 1([0-9])

Character Class[0-9]

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

\1{2}the text saved by group 1, repeated exactly 2 times

Character Class[-. ]*

*matches any number of characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

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

Character Class[-. ]*

*matches any number of characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

\1{4}the text saved by group 1, repeated exactly 4 times

$end of string, or before its final line terminator

\(?optionally matches the literal ( (40₁₀ / 50₈ / 28₁₆)

Group 2([0-9]{3})

Character Class[0-9]{3}

{3}matches exactly 3 characters from the set below:

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

\)?optionally matches the literal ) (41₁₀ / 51₈ / 29₁₆)

Character Class[-. ]?

?matches at most one character from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

Group 3([0-9]{3})

Character Class[0-9]{3}

{3}matches exactly 3 characters from the set below:

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

Character Class[-. ]?

?matches at most one character from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

Group 4([0-9]{4})

Character Class[0-9]{4}

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

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

$end of string, or before its final line terminator

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^(?=(?!([0-9])\1{2}[-. ]*\1{3}[-. ]*\1{4}$))\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$

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111-111-1114