HI
how can i ensure that a string contains no digits using regex in ruby?
thanks
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2 Answers
\D is the character class meaning "not digit", so you could do
^\D*$
^ forces it to start at the beginning of the line, $ forces it to continue to the end of the line.
2 Comments
Donald Miner
I had to look up a reference to see if \D existed, I had an inkling it did! To be honest, I think [^0-9] is more readable.
Joshua Cheek
As a general rule, if there is a matcher for it, I go with that, because if there is some other language where the English character maps to some other Unicode character, then the matchers should understand and be able to handle that. I don't know if language uses other characters for digits, but if they do, \d and \D will be correct for them too, where [0-9] and [^0-9] will not.
You can scan for any digit, then use !~ to match when if it cannot find one.
'1234' !~ /\d/ # => false
'12.34' !~ /\d/ # => false
'abc1def' !~ /\d/ # => false
'a1b2c3d' !~ /\d/ # => false
'12abc' !~ /\d/ # => false
'abc12' !~ /\d/ # => false
'oi9' !~ /\d/ # => false
'abc' !~ /\d/ # => true
'ABC' !~ /\d/ # => true
'aBcD' !~ /\d/ # => true
'' !~ /\d/ # => true
'日本語' !~ /\d/ # => true
'~!@#%^&*()}' !~ /\d/ # => true
