regex101: PCRE (Legacy) Substitution Workspace

Comment:проверка корректности даты в формате ГГГГ-ММ-ДД без проверки YYYY-02-29 в високосных годах (нужно доделать)

Positive Lookahead(?=^ (?:19|20)\d\d #1900...2099 - (?: (?:0[1-9]|1[012]) #01...12 - (?:0?[1-9]|[12]\d) #01...29 | (?:0[13-9]|1[012]) #monthForDay30 - 30 | (?:0[13578]|1[02]) #monthForDay31 - 31 ) $)

^start of line

Non-Capturing Group(?:19|20)

1st Alternative19

19the literal text 19

2nd Alternative20

20the literal text 20

\da digit

Comment:1900...2099

- the literal text -

Non-Capturing Group(?: (?:0[1-9]|1[012]) #01...12 - (?:0?[1-9]|[12]\d) #01...29 | (?:0[13-9]|1[012]) #monthForDay30 - 30 | (?:0[13578]|1[02]) #monthForDay31 - 31 )

1st Alternative (?:0[1-9]|1[012]) #01...12 - (?:0?[1-9]|[12]\d) #01...29

Non-Capturing Group(?:0[1-9]|1[012])

1st Alternative0[1-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

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

2nd Alternative1[012]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[012]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Comment:01...12

- the literal text -

Non-Capturing Group(?:0?[1-9]|[12]\d)

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]\d

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\da digit

Comment:01...29

2nd Alternative (?:0[13-9]|1[012]) #monthForDay30 - 30

Non-Capturing Group(?:0[13-9]|1[012])

1st Alternative0[13-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[13-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3-9one character from 3 (51₁₀) to 9 (57₁₀)

2nd Alternative1[012]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[012]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Comment:monthForDay30

- 30 the literal text -30

3rd Alternative (?:0[13578]|1[02]) #monthForDay31 - 31

Non-Capturing Group(?:0[13578]|1[02])

1st Alternative0[13578]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[13578]

2nd Alternative1[02]

Comment:monthForDay31

- 31 the literal text -31

$end of line

^start of line

Group year(?<year>\d{4})

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group month(?<month>\d{2})

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group day(?<day>\d{2})

$end of line

Global pattern flags

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

s modifier: single line. Allows a dot to match line terminators

g modifier: global. Finds all matches instead of stopping after the first

Search reference

Regular Expression

#проверка корректности даты в формате ГГГГ-ММ-ДД без проверки YYYY-02-29 в високосных годах (нужно доделать)

(?=^
    (?:19|20)\d\d        #1900...2099
    -
    (?:    (?:0[1-9]|1[012])   #01...12
           -
           (?:0?[1-9]|[12]\d)  #01...29
        |  (?:0[13-9]|1[012])  #monthForDay30 
           - 
           30
        |  (?:0[13578]|1[02]) #monthForDay31 
           - 
           31
    )
$)
^(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})$

Test String
New

Substitution
Processing...

${year}-${month}-${day}

Regular Expression

Test StringNew

SubstitutionProcessing...

Test String
New

Substitution
Processing...