Analysis of PHP stripos () Functions and precautions

Definition and usage
The stripos () function returns the position where the string first appears in another string.

If this string is not found, false is returned.

Syntax
Stripos (string, find, start)

Parameters	Description
String	Required. Specifies the string to be searched.
Find	Required. Specifies the characters to be searched.
Start	Optional. Specifies the location where the search starts.

Tips and comments
Note: This function is case insensitive. To perform a case-sensitive search, use the strpos () function.
This function returns the position of the first occurrence of the string in another string. So this location may be 0.
When the return value is 0, you must note that
Copy codeThe Code is as follows:
If (stripos ($ r, 'A') = false ){

// 0 indicates that a exists in total with $ r, but because 0 and false are equal, the following code is executed:
}
If (stripos ($ r, 'A') == false ){

// In this case, we must use all equal values.

}