CODEWITHSUNDEEP
javascriptregex
Melvins138
Melvins138

Reputation: 81

REGEX Check for Character at Beginning or End of string

I need to validate an entry in a form. I was using /^\d{9}[A-Z]$/ to check for 9 digits and a single uppercase character. I was informed that the input could be a single uppercase character and 9 digits OR 9 digits and a single uppercase character, but not both a single uppercase character then 9 digits then a single uppercase character.

Basically either A123456789 or 123456789A is acceptable, but not A123456789A

What RegEx would I use to verify that there is at least one single uppercase character at either at the beginning or end, but not both... followed or preceded by 9 digits?

Upvotes: 1

Views: 2131

Answers (2)

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89557

If your regex flavour supports it, you can use a conditional:

^([A-Z])?\d{9}(?(1)|[A-Z])$

Explanation:

^
([A-Z])?  # optional capture group
\d{9}
(?(1)     # if capture group 1 exist
          # then there is nothing
  |       # ELSE
    [A-Z] # there is an uppercase letter
)
$

Upvotes: 0

Denys Séguret
Denys Séguret

Reputation: 382150

If you want it in one regex, this should do :

(^\d{9}[A-Z]$)|(^[A-Z]\d{9}$)

Upvotes: 6

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