Question

in my program php, I want the user doesn’t enter any caracters except the alphabets
like that : “dgdh”, “sgfdgdfg” but he doesn’t enter the numbers or anything else like “7657” or “gfd(-” or “fd54”
I tested this function but it doesn’t cover all cases :

preg_match("#[^0-9]#",$_POST['chaine'])

how can I achieve that, thank you in advance

Answer 1

The simplest can be

preg_match('/^[a-z]+$/i', $_POST['chaine'])

the i modifier is for case-insensitive. The + is so that at least one alphabet is entered. You can change it to * if you want to allow empty string. The anchor ^ and $ enforce that the whole string is nothing but the alphabets. (they represent the beginning of the string and the end of the string, respectively).

---

If you want to allow whitespace, you can use:

Whitespace only at the beginning or end of string:

preg_match('/^\s*[a-z]+\s*$/i', $_POST['chaine'])

Any where:

preg_match('/^[a-z][\sa-z]*$/i', $_POST['chaine'])    // at least one alphabet

Only the space character is allowed but not other whitespace:

preg_match('/^[a-z][ a-z]*$/i', $_POST['chaine'])