regex101: US phone number

Group 1(\+?(\b1)?[\ .\/-]?((?(2)|(\b))|($))\d{3}(?(?<=\(\d{3})$|)[\ .\/-]?)?

?repeats the group contents below at most once:

\+?optionally matches the literal + (43₁₀ / 53₈ / 2B₁₆)

Group 2(\b1)?

?repeats the group contents below at most once:

\ban ASCII word boundary

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[\ .\/-]?

?matches at most one character from the set below:

\ the literal (32₁₀ / 40₈ / 20₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 3((?(2)|(\b))|(\())

1st Alternative(?(2)|(\b))

Condition(?(2)|(\b))

Uses the first branch if group 2 matched

If the condition is true, match this branch: — matches an empty string

Otherwise, match this branch:(\b)

Group 4(\b)

\ban ASCII word boundary

2nd Alternative(\()

Group 5(\()

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

\d{3}a digit, repeated exactly 3 times

Condition(?(?<=$\d{3})$|)

Uses the first branch if the lookaround matches

Positive Lookbehind(?<=\(\d{3})

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

\d{3}a digit, repeated exactly 3 times

If the condition is true, match this branch:\)

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

Otherwise, match this branch: — matches an empty string

Character Class[\ .\/-]?

?matches at most one character from the set below:

\ the literal (32₁₀ / 40₈ / 20₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Condition(?(1)|\b)

Uses the first branch if group 1 matched

If the condition is true, match this branch: — matches an empty string

Otherwise, match this branch:\b

\ban ASCII word boundary

\d{3}a digit, repeated exactly 3 times

Character Class[\ .\/-]?

?matches at most one character from the set below:

\ the literal (32₁₀ / 40₈ / 20₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{4}a digit, repeated exactly 4 times

Character Class[\ ]?

?matches at most one character from the set below:

\ the literal (32₁₀ / 40₈ / 20₁₆)

Group 6([xX][\ ]?\d{1,5})?

?repeats the group contents below at most once:

Character Class[xX]

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Character Class[\ ]?

?matches at most one character from the set below:

\ the literal (32₁₀ / 40₈ / 20₁₆)

\d{1,5}a digit, repeated between 1 and 5 times

\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

(\+?(\b1)?[\ .\/-]?((?(2)|(\b))|(\())\d{3}(?(?<=\(\d{3})\)|)[\ .\/-]?)?(?(1)|\b)\d{3}[\ .\/-]?\d{4}[\ ]?([xX][\ ]?\d{1,5})?\b

Unit Tests

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