Regular Expressions 101

Pro

^start of line

Positive Lookahead(?=.{18})

.{18}any Unicode character (except for line terminators), repeated exactly 18 times

Non-Capturing Group(?:[a-zA-Z]+\d|\d+[a-zA-Z])

1st Alternative[a-zA-Z]+\d

Character Class[a-zA-Z]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

\da Unicode decimal digit

2nd Alternative\d+[a-zA-Z]

\d+a Unicode decimal digit, repeated at least once

Character Class[a-zA-Z]

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

Character Class[a-zA-Z\d]*

*matches any number of characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

\da Unicode decimal digit

$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

Detailed match information will be displayed here automatically.

25 tokens

^(?=.{18})(?:[a-zA-Z]+\d|\d+[a-zA-Z])[a-zA-Z\d]*$

New

1Z83E0590391137855
55t5555t5t5tttt5t5555tttttttgggggggsss
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