CODEWITHSUNDEEP
regex
Zerobu
Zerobu

Reputation: 2691

Regex to test character length of a string

How do I test to see the length of a string using regex?

For example, how do i match a string if it contains only 1 character?

Upvotes: 4

Views: 9852

Answers (4)

Seth Robertson
Seth Robertson

Reputation: 31441

/^.\z/s

The above requires perl compatible regexps. The trick is that /^.$/ might match "x" and "x\n". Adding /s modifier doesn't help there.

Upvotes: 0

Yuriy Faktorovich
Yuriy Faktorovich

Reputation: 68667

^.$

But most frameworks include methods that will return string length, which you should use instead of regex for this.

Upvotes: 4

CanSpice
CanSpice

Reputation: 35788

Matching a single character would be (using Perl regex):

/\A.\z/s

\A means "start of the string", . means "any character", and \z means "end of the string". Without the \A and \z you'll match any string that's longer than one character.

Edit: But really you should be doing something like:

if( length($string) == 1 ) {
  ...
}

(using Perl as an example)

Edit2: Previously I had /^.$/ but, as Seth pointed out, this allows matches on strings that are two characters long where the last character is \n. The \A...\z construct fixes that.

Upvotes: 1

Phrogz
Phrogz

Reputation: 303206

Anchor to the start and end of string and match one character. In many languages:

^.{1}$

In Ruby's Regex:

\A.{1}\z

Upvotes: 4

Related Questions