正则表达式检查字符串只包含字母和数字，但不仅包括数字

Question

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

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 2

This should do it:

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

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

Answer 3

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

Answer 4

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 5

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

Answer 6

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

• (?=.*[az]) 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 7

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?

Answer 8

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

Answer 9

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

翻译：从头开始，匹配0或更多数字，然后匹配至少一个字母，然后匹配零个或多个字母或数字，直到结束。

Answer 10

这应该工作^([a-zA-Z0-9]*)([a-zA-Z]+)([a-zA-Z0-9]*)$ EDIT sry得到了*而且+搞砸了