regex101: Python Match Workspace

Negative Lookbehind(?<!\d)

\da Unicode decimal digit

Non-Capturing Group(?:(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(3[47][0-9]{13})|(?:5[1-5][0-9]{14}))(?!\d))

Non-Capturing Group(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(3[47][0-9]{13})|(?:5[1-5][0-9]{14}))

1st Alternative(?:(4[0-9]{12}(?:[0-9]{3})?))

Non-Capturing Group(?:(4[0-9]{12}(?:[0-9]{3})?))

Group 1(4[0-9]{12}(?:[0-9]{3})?)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

Character Class[0-9]{12}

{12}matches exactly 12 characters from the set below:

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

Non-Capturing Group(?:[0-9]{3})?

?repeats the group contents below at most once:

Character Class[0-9]{3}

{3}matches exactly 3 characters from the set below:

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

2nd Alternative(3[47][0-9]{13})

Group 2(3[47][0-9]{13})

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[47]

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

7the literal 7 (55₁₀ / 67₈ / 37₁₆)

Character Class[0-9]{13}

{13}matches exactly 13 characters from the set below:

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

3rd Alternative(?:5[1-5][0-9]{14})

Non-Capturing Group(?:5[1-5][0-9]{14})

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

Character Class[1-5]

1-5one character from 1 (49₁₀) to 5 (53₁₀)

Character Class[0-9]{14}

{14}matches exactly 14 characters from the set below:

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

Negative Lookahead(?!\d)

\da Unicode decimal digit

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[0-9]{12}(?:[0-9]{3})?))|(3[47][0-9]{13})|(?:5[1-5][0-9]{14}))(?!\d))

New

   474051514405037899  is NOT Visa
4740515144050,378282246310005  is Visa and Amex 378282246310005,4740515144050
4740515144050,378282246310005  is Visa and Amex 
4740515144050378282246310005 is NOT Visa or Amex 4740515144050378282246310005
378282246310005 is Amex Card
378282246310005is Amex  a378282246310005
3782822463100059999 is NOT AmexCard
9378282246310005 is NOT AmexCard



(?:\D|^)(?:(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(3[47][0-9]{13}))(?:\D|$)) -using not-capture groups  /gm multi-line

(?<!\d)(?:(?:(4[0-9]{12}(?:[0-9]{3})?))(?!\d)) -visa using look-around

(?<!\d)(?:(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(3[47][0-9]{13}))(?!\d)) -working
(?<!\d)(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(?:(3[47][0-9]{13}))(?!\d)) visa pattern first not working -incorrectly match even following by digits

(?<!\d)(?:(?:(3[47][0-9]{13})|(?:(4[0-9]{12}(?:[0-9]{3})?)))(?!\d))  visa pattern last  working correctly 

(?<!\d)(?:(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(3[47][0-9]{13})|(?:5[1-5][0-9]{14}))(?!\d)) -Visa,Amex,MC working
(?<!\d)(?:(?:(?:(4[0-9]{12}(?:[0-9]{3})?))|(?:5[1-5][0-9]{14})|(3[47][0-9]{13}))(?!\d))  -Visa,MC,Amex working

(?<!\d)(?:(?:(3[47][0-9]{13})|(?:(4[0-9]{12}(?:[0-9]{3})?))|(?:5[1-5][0-9]{14}))(?!\d)) -Amex,Visa,MC working

Regular Expressions 101

Regular Expression

Substitution