Convert numbers to letters to generate Excel column labels

Provides various official and user-released code examples. For code reference, you are welcome to exchange and learn how to dynamically configure the ing between Excel and database tables during Excel upload and resolution, when an array index is associated with a column in Excel, You need to convert the index value to an Excel column label. Therefore, you have written this method and now post the code, if you have any better methods, please share them with us. Thank you!
/**
* Convert numbers to letters (similar to Excel columns)
* @ Param Int $ index Value
* @ Param Int $ start value
* @ Return String return letters
* @ Author Anyon Zou
* @ Date
*/
Function IntToChr ($ index, $ start = 65 ){
$ Str = '';
If (floor ($ index/26)> 0 ){
$ Str. = IntToChr (floor ($ index/26)-1 );
}
Return $ str. chr ($ index % 26 + $ start );
}

/**
* Test
*/
Function test (){
Echo IntToChr (0); // #
Echo IntToChr (1); // # B
//...
Echo IntToChr (27); // # AB
}

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