[PHP] string-access substring

Want to know whether a string contains a specific substring. For example, you want to check whether an email address contains @. Problem

Want to know whether a string contains a specific substring. For example, you want to check whether an email address contains @.

Solution

If (strpos ($ _ POST ['email '],' @ ') === false) {echo 'there was no @ in the e-mail address! ';}

Discussion

1. The return value of strpos () is the first position of the substring in the string.

2. If no substring exists in the string, strpos () returns false.

3. If the substring is at the starting position of the string, strpos () returns 0 because position 0 indicates the starting position of the string.

4. To distinguish between 0 and false, the constant operator (=) or non-constant operator (! =)

5. In the preceding example, use = to compare the return value of strpos () with false. This test succeeds only when strpos () returns false. if strpos () returns 0 or any other number, the test fails.

   
   

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