Regular Expressions 101

data/the literal text data/ (case sensitive)

Group yyyy(?P<yyyy>[12]\d{3})

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

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

Group mm(?P<mm>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)

Group dd(?P<dd>3[0-1]|[1-2][0-9]|0?[1-9])

1st Alternative3[0-1]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[0-1]

0-1one character from 0 (48₁₀) to 1 (49₁₀)

2nd Alternative[1-2][0-9]

Character Class[1-2]

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

Character Class[0-9]

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

3rd 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)

\ba Unicode 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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

data/(?P<yyyy>[12]\d{3})(?P<mm>0?[1-9]|1[0-2])(?P<dd>3[0-1]|[1-2][0-9]|0?[1-9])\b

data/20221231/file01.csv