CODEWITHSUNDEEP
ruby-on-railsrubyregex
Tintin81
Tintin81

Reputation: 10225

How to create a regular expression to match specific substrings inside brackets?

In my Ruby on Rails app I need a regex that accepts the following values:

I am still new to regular expressions and I came up with this:

/\A[a-zA-Z._}{#-]*\z/

This works pretty well already, however it also matches strings that should not be allowed such as:

}FOO or {YYY}

Can anybody help?

Upvotes: 1

Views: 42

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 627507

You may use

/\A(?:\{(?:DD|MM|YY|N{2,6})\}|[A-Za-z_.#-])*\z/

See Rubular demo

  • \A - start of string anchor
  • (?:\{(?:DD|MM|YY|N{2,6})\}|[A-Za-z_.#-])* - a non-capturing group ((?:...) that only groups sequences of atoms and does not create submatches/subcaptures) zero or more occurrences of:
    • \{(?:DD|MM|YY|N{2,6})\} - a { then either DD, or MM, YY, 2 to 6N followed with }
    • | - or
    • [A-Za-z_.#-] - 1 char from the set (ASCII letter, _, ., # or -)
  • \z - end of string.

Upvotes: 4

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