如何检查字符串是否仅由字母和数字组成？ （PHP）

Question

Title says it all: I am checking to see if a user's username contains anything that isn't a number or letter, such as €{¥]^}+<€, punctuation, spaces or even things like âæłęč. Is this possible in php?

Answer 1

You can use the ctype_alnum() function in PHP.

From the manual..

Check for alphanumeric character(s)
Returns TRUE if every character in text is either a letter or a digit, FALSE otherwise.

var_dump(ctype_alnum("æøsads")); // false
var_dump(ctype_alnum("123asd")); // true

• Live demo at https://3v4l.org/5etr7