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1st Alternative\b((0?[1-9]|[12][0-9]|3[01])[-/.\s](0?[1-9]|1[0-2])[-/.\s](19[0-9]{2}|200[0-9]))

\ban ASCII word boundary

Group 1((0?[1-9]|[12][0-9]|3[01])[-/.\s](0?[1-9]|1[0-2])[-/.\s](19[0-9]{2}|200[0-9]))

Group 2(0?[1-9]|[12][0-9]|3[01])

1st Alternative0?[1-9]

0?optionally matches the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

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

2nd Alternative[12][0-9]

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-9]

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

3rd Alternative3[01]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[-/.\s]

-the literal - (45₁₀ / 55₈ / 2D₁₆)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\sany whitespace character

Group 3(0?[1-9]|1[0-2])

1st Alternative0?[1-9]

0?optionally matches the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

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

2nd Alternative1[0-2]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-2]

0-2one character from 0 (48₁₀) to 2 (50₁₀)

Character Class[-/.\s]

-the literal - (45₁₀ / 55₈ / 2D₁₆)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\sany whitespace character

Group 4(19[0-9]{2}|200[0-9])

1st Alternative19[0-9]{2}

19the literal text 19

Character Class[0-9]{2}

{2}matches exactly 2 characters from the set below:

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

2nd Alternative200[0-9]

200the literal text 200

Character Class[0-9]

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

2nd Alternative((0?[1-9]|1[0-2])[-/.\s](0?[1-9]|[12][0-9]|3[01])[-/.\s](19[0-9]{2}|200[0-9]))

Group 5((0?[1-9]|1[0-2])[-/.\s](0?[1-9]|[12][0-9]|3[01])[-/.\s](19[0-9]{2}|200[0-9]))

Group 6(0?[1-9]|1[0-2])

1st Alternative0?[1-9]

2nd Alternative1[0-2]

Character Class[-/.\s]

Group 7(0?[1-9]|[12][0-9]|3[01])

Character Class[-/.\s]

Group 8(19[0-9]{2}|200[0-9])

3rd Alternative(([012][1-9]|3[01])(st|nd|rd|th)?\s(?i:Jan|Feb|Fév|Mar|Apr|Avr|May|Mai|Jun|Juin|Jul|Juil|Aug|Sep|Sept|Oct|Nov|Dec|Déc)\s(?:19[0-9]{2}|200[0-9]))

4th Alternative((?i:Jan|Feb|Fév|Mar|Apr|Avr|May|Mai|Jun|Juin|Jul|Juil|Aug|Sep|Sept|Oct|Nov|Dec|Déc)\s(?:0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\s(?:19[0-9]{2}|200[0-9]))

5th Alternative((0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\s(?i:January|janvier|February|fevrier|février|March|mars|April|avril|May|mai|June|juin|July|juillet|August|aout|août|September|septembre|October|octobre|November|novembre|December|décembre|decembre)\s(?:19[0-9]{2}|200[0-9]))

6th Alternative((?iu:January|janvier|February|fevrier|février|March|mars|April|avril|May|mai|June|juin|July|juillet|August|aout|août|September|septembre|October|octobre|November|novembre|December|décembre|decembre)\s(?:0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\s(?:19[0-9]{2}|200[0-9]))

7th Alternative(0?[1-9]|1[0-2])[-\/.\s](0?[1-9]|[12][0-9]|3[01])[-\/.\s](19|20)0[0-9]

8th Alternative(19|20)0[0-9][-\/.\s](0?[1-9]|1[0-2])[-\/.\s](0?[1-9]|[12][0-9]|3[01])\b

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

\b((0?[1-9]|[12][0-9]|3[01])[-/.\s](0?[1-9]|1[0-2])[-/.\s](19[0-9]{2}|200[0-9]))|((0?[1-9]|1[0-2])[-/.\s](0?[1-9]|[12][0-9]|3[01])[-/.\s](19[0-9]{2}|200[0-9]))|(([012][1-9]|3[01])(st|nd|rd|th)?\s(?i:Jan|Feb|Fév|Mar|Apr|Avr|May|Mai|Jun|Juin|Jul|Juil|Aug|Sep|Sept|Oct|Nov|Dec|Déc)\s(?:19[0-9]{2}|200[0-9]))|((?i:Jan|Feb|Fév|Mar|Apr|Avr|May|Mai|Jun|Juin|Jul|Juil|Aug|Sep|Sept|Oct|Nov|Dec|Déc)\s(?:0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\s(?:19[0-9]{2}|200[0-9]))|((0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\s(?i:January|janvier|February|fevrier|février|March|mars|April|avril|May|mai|June|juin|July|juillet|August|aout|août|September|septembre|October|octobre|November|novembre|December|décembre|decembre)\s(?:19[0-9]{2}|200[0-9]))|((?iu:January|janvier|February|fevrier|février|March|mars|April|avril|May|mai|June|juin|July|juillet|August|aout|août|September|septembre|October|octobre|November|novembre|December|décembre|decembre)\s(?:0?[1-9]|[12][0-9]|3[01])(st|nd|rd|th)?\s(?:19[0-9]{2}|200[0-9]))|(0?[1-9]|1[0-2])[-\/.\s](0?[1-9]|[12][0-9]|3[01])[-\/.\s](19|20)0[0-9]|(19|20)0[0-9][-\/.\s](0?[1-9]|1[0-2])[-\/.\s](0?[1-9]|[12][0-9]|3[01])\b

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31 March 2009
March 31 2009
31 mars 2009
May 10th 1989
April 2nd 2008
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2009 1 31
31st december 2009
31 décembre 2009
31 Decembre 2009
2009/02/01
2009.01.01
2009 01 01
31 03 2009
12 31 2009

Regular Expressions 101

Regular Expression

Extraction