Regex: How to match a string that is not only numbers

Question

Is it possible to write a regular expression that matches all strings that does not only contain numbers? If we have these strings:

• abc

Answer 1

I had to do something similar in MySQL and the following whilst over simplified seems to have worked for me:

where fieldname regexp ^[a-zA-Z0-9]+$ and fieldname NOT REGEXP ^[0-9]+$

This shows all fields that are alphabetical and alphanumeric but any fields that are just numeric are hidden. This seems to work.

example:

name1 - Displayed
name - Displayed
name2 - Displayed
name3 - Displayed
name4 - Displayed
n4ame - Displayed
324234234 - Not Displayed

Answer 2

jjnguy had it correct (if slightly redundant) in an earlier revision.

.*?[^0-9].*

@Chad, your regex,

\b.*[a-zA-Z]+.*\b

should probably allow for non letters (eg, punctuation) even though Svish's examples didn't include one. Svish's primary requirement was: not all be digits.

\b.*[^0-9]+.*\b

Then, you don't need the + in there since all you need is to guarantee 1 non-digit is in there (more might be in there as covered by the .* on the ends).

\b.*[^0-9].*\b

Next, you can do away with the \b on either end since these are unnecessary constraints (invoking reference to alphanum and _).

.*[^0-9].*

Finally, note that this last regex shows that the problem can be solved with just the basics, those basics which have existed for decades (eg, no need for the look-ahead feature). In English, the question was logically equivalent to simply asking that 1 counter-example character be found within a string.

We can test this regex in a browser by copying the following into the location bar, replacing the string "6576576i7567" with whatever you want to test.

javascript:alert(new String("6576576i7567").match(".*[^0-9].*"));

Answer 3

.*[^0-9]{1,}.*

Works fine for us.

We want to use the used answer, but it's not working within YANG model.

And the one I provided here is easy to understand and it's clear: start and end could be any chars, but, but there must be at least one NON NUMERICAL characters, which is greatest.

Answer 4

/^\d*[a-z][a-z\d]*$/

May be a digit at the beginning, then at least one letter, then letters or digits

Answer 5

If we want to restrict valid characters so that string can be made from a limited set of characters, try this:

(?!^\d+$)^[a-zA-Z0-9_-]{3,}$

or

(?!^\d+$)^[\w-]{3,}$

/\w+/: Matches any letter, number or underscore. any word character