Regex to get length of group of character classes

user_10783453 0
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I have a workaround for this, but was hoping to find a purely regex solution.

The requirements are:

  • has one required character
  • only pulls from a pool of approved characters
  • minimum length of 4
  • single word, no whitespace

e.g.
required character: m
pool of characters: [a,b,e,l]

Possible matches:
mabel
abemal
labeam

won't match:
a mael
ama
label

So far I have this expression, but putting a {4,} after it thinks I'm talking about multiplying word matches by 4.
^\b(?:[abel]*[m]+[abel]*)\b

regex
1 Answers

You can use

^(?=.*[m])[abelm]{4,}$

^ start of a line or string

Positive Lookahead (?=.*[m])
Asserts that the string contains at least 1 m character

[abelm]{4,} matches characters in the list abelm
between 4 and unlimited times, as many times as possible.
(greedy) (case sensitive)

$ end of a line or string

user_40034190
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