regex101: regex expression to DateTime checking in YYYY-MM-DDTHH:MM:SS[+/-]HH:SS

Group 1(^((\d{4}-(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))))|((\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))))|((\d{4}-(0[2]-(0[1-9]|[1-2]\d)))))T(([01]\d|2[0-3]):([0-5]\d):([0-5]\d))?([+-][0-2]\d:[0-5]\d)$)

^start of line

Group 2((\d{4}-(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))))|((\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))))|((\d{4}-(0[2]-(0[1-9]|[1-2]\d)))))

1st Alternative(\d{4}-(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))))

Group 3(\d{4}-(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))))

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

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 4(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01])))

Group 5((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))

Group 6(0[13578]|[1][02])

1st Alternative0[13578]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[13578]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

7the literal 7 (55₁₀ / 67₈ / 37₁₆)

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

2nd Alternative[1][02]

Character Class[1]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[02]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 7(0[1-9]|[1-2]\d|3[01])

1st Alternative0[1-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

2nd Alternative[1-2]\d

Character Class[1-2]

1-2one character from 1 (49₁₀) to 2 (50₁₀)

\da digit

3rd Alternative3[01]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2nd Alternative((\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))))

Group 8((\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))))

Group 9(\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0]))))

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

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 10(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))

Group 11((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0]))

Group 12(0[469]|[1][1])

1st Alternative0[469]

2nd Alternative[1][1]

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 13(0[1-9]|[1-2]\d|[3][0])

3rd Alternative((\d{4}-(0[2]-(0[1-9]|[1-2]\d))))

Tthe literal T (84₁₀ / 124₈ / 54₁₆) (case sensitive)

Group 18(([01]\d|2[0-3]):([0-5]\d):([0-5]\d))?

Group 22([+-][0-2]\d:[0-5]\d)

$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

Search reference

Regular Expression

(^((\d{4}-(((0[13578]|[1][02])-(0[1-9]|[1-2]\d|3[01]))))|((\d{4}-(((0[469]|[1][1])-(0[1-9]|[1-2]\d|[3][0])))))|((\d{4}-(0[2]-(0[1-9]|[1-2]\d)))))T(([01]\d|2[0-3]):([0-5]\d):([0-5]\d))?([+-][0-2]\d:[0-5]\d)$)

Unit Tests

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