"PHP" string-access substring

Problem

Want to know if a string contains a specific substring. For example, want to see if an email address contains an @.

Solve

if (Strpos ($_post[' email '), ' @ ') = = = False) {    echo ' there is no @ in the e-mail address! ';}

Discuss

1. The return value of Strpos () is the first occurrence of a substring in a string

2. If there is no substring at all in the string, Strpos () returns false

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

4. To distinguish between 0 and false, you must use the identity operator (= = =) or the non-identity operator (!==)

5. The above example uses the = = = To compare the return value of Strpos () with false. This test succeeds only if Strpos () returns false, and if Strpos () returns 0 or any other number, the test will not succeed