Regular Expressions 101

^start of line

Non-Capturing Group(?:[A-Za-z0-9+\/]{4})*

*repeats the group contents below any number of times:

Character Class[A-Za-z0-9+\/]{4}

{4}matches exactly 4 characters from the set below:

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

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

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

+the literal + (43₁₀ / 53₈ / 2B₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Non-Capturing Group(?:[A-Za-z0-9+\/]{4}|[A-Za-z0-9+\/]{3}=|[A-Za-z0-9+\/]{2}==)

1st Alternative[A-Za-z0-9+\/]{4}

Character Class[A-Za-z0-9+\/]{4}

{4}matches exactly 4 characters from the set below:

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

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

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

+the literal + (43₁₀ / 53₈ / 2B₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

2nd Alternative[A-Za-z0-9+\/]{3}=

Character Class[A-Za-z0-9+\/]{3}

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

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

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

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

+the literal + (43₁₀ / 53₈ / 2B₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

=the literal = (61₁₀ / 75₈ / 3D₁₆)

3rd Alternative[A-Za-z0-9+\/]{2}==

Character Class[A-Za-z0-9+\/]{2}

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

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

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

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

+the literal + (43₁₀ / 53₈ / 2B₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

==the literal text ==

$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

No unit tests · Add a test to get started

Search reference

Regular Expression

^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{4}|[A-Za-z0-9+\/]{3}=|[A-Za-z0-9+\/]{2}==)$

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