regex to check the string contains only letter and numbers but not only numbers

Question

hi, I need a help with regex which checks the string contains only letter and numbers but not only numbers

Valid

* letters
* 1wret
* 0123chars
* chars0123
* cha2rs

Invalid

* 1324
* xcvxxc%$#
* xcv123xxc%$#
* _012chars
* _test

Answer 1

[a-z0-9]*[a-z]+[a-z0-9]*

Answer 2

([0-9]*[a-zA-Z]+)+

Answer 3

Instead of using a regular expression, you can also use the ctype_*() functions:

var_dump(ctype_alnum('letters') && !ctype_digit('letters'));     // bool(true)
var_dump(ctype_alnum('0123chars') && !ctype_digit('0123chars')); // bool(true)
var_dump(ctype_alnum('1324') && !ctype_digit('1324'));           // bool(false)
var_dump(ctype_alnum('xcvxxc%$#') && !ctype_digit('xcvxxc%$#')); // bool(false)

But if you want a regular expression, you can use this:

var_dump(preg_match('/^[a-z0-9]*[a-z]+[a-z0-9]*$/i', $input));

Answer 4

this should work ^([a-zA-Z0-9]*)([a-zA-Z]+)([a-zA-Z0-9]*)$ EDIT sry got the * and the + messed up

Answer 5

^([a-zA-Z0-9]*)([a-zA-Z]+)([a-zA-Z0-9]*)$

Answer 6

This should do it:

^[0-9]*[a-zA-Z]+[a-zA-Z0-9]*$

This requires at least one character of [a-zA-Z].

Answer 7

^[0-9]*[a-zA-Z]+[0-9a-zA-Z]*$

translated: from the beginning, match 0 or more numbers, then match at least one letter, then match zero or more letters or numbers until the end.

Answer 8

Here are the components of the regex we're going to use:

• ^ and $ are the beginning and end of the string anchors respectively
• \d matches a digit
• [a-zA-Z] matches a letter
• [a-zA-Z\d] matches a letter or a digit
• * is "zero-or-more" repetition

With these, we can now compose the regex we need (see on rubular.com):

^\d*[a-zA-Z][a-zA-Z\d]*$

Here's an explanation of the pattern:

from the beginning...  till the end
|                      |
^\d*[a-zA-Z][a-zA-Z\d]*$
 \_/\______/\_________/

The 3 parts are:

• Maybe some digits as a prefix...
• But then definitely a letter!
• And then maybe some digits and letters as a suffix

References

• regular-expressions.info/Character Class, Anchors, and Repetition

Answer 9

^(?=.*[a-z])[a-zA-Z0-9]+$

• (?=.*[a-z]) positive lookahead to make sure that there is at least one letter in the string (but doesn't consume any characters - gives up the matched characters as soon as it returns (in this case, as soon as it finds a letter)).
• [a-zA-Z0-9]+ make sure string contains only alphanumeric characters.
• ^ and $ are start and end of string delimiters.

Answer 10

Personally (I hate regex and find them generally to be hard to maintain), I'd do it in two steps.

1. Is it all alphanumeric?
2. Is there at least one letter?