regex101: Java Match Workspace

Pro

Negative Lookbehind(?<![abc])

Character Class[abc]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

Comment: No "a", "b", "c" allowed immediately on the left

Positive Lookahead(?=(?:[bc]*a){3})

Non-Capturing Group(?:[bc]*a){3}

{3}repeats the group contents below exactly 3 times:

Character Class[bc]*

*matches any number of characters from the set below:

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

Comment: At least three "a"s

Positive Lookahead(?=(?:[ac]*b){3})

Non-Capturing Group(?:[ac]*b){3}

{3}repeats the group contents below exactly 3 times:

Character Class[ac]*

*matches any number of characters from the set below:

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

Comment: At least three "b"s

Non-Capturing Group(?: # Either (?=[ab]*(?![abc])) # only "a" or "b"s allowed until a location not followed with "a", "b" or "c" | # or (?=(?:[ab]*c){3}) # At least three "c"s )

1st Alternative # Either (?=[ab]*(?![abc])) # only "a" or "b"s allowed until a location not followed with "a", "b" or "c"

Comment: Either

Positive Lookahead(?=[ab]*(?![abc]))

Character Class[ab]*

*matches any number of characters from the set below:

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

Negative Lookahead(?![abc])

Character Class[abc]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

Comment: only "a" or "b"s allowed until a location not followed with "a", "b" or "c"

2nd Alternative # or (?=(?:[ab]*c){3}) # At least three "c"s

Comment: or

Positive Lookahead(?=(?:[ab]*c){3})

Non-Capturing Group(?:[ab]*c){3}

{3}repeats the group contents below exactly 3 times:

Character Class[ab]*

*matches any number of characters from the set below:

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

Comment: At least three "c"s

Character Class[abc]+

+matches at least one character from the set below:

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

Comment: Match and consume one or more "a", "b" or "c" chars

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

x modifier: extended. Ignores unescaped whitespace and comments, including inside character classes

27 tokens

Regular Expression

(?<![abc])              # No "a", "b", "c" allowed immediately on the left
(?=(?:[bc]*a){3})       # At least three "a"s
(?=(?:[ac]*b){3})       # At least three "b"s
(?:                     # Either
   (?=[ab]*(?![abc]))   #  only "a" or "b"s allowed until a location not followed with "a", "b" or "c"
 |                      #  or
   (?=(?:[ab]*c){3})    # At least three "c"s
)
[abc]+                  # Match and consume one or more "a", "b" or "c" chars

Unit Tests

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