PHP String Case Conversion

Strtoupper (), Strtolower (), Ucfirst (), Ucfirst (), Ucwords (), Mb_strtoupper (), Mb_strtolower (), and Mb_convert_case () These eight functions differ and relate to:

Function name	Scope of Use	Function
Strtoupper	PHP4,PHP5	Convert a string to uppercase
Strtolower	PHP4,PHP5	Convert a string to lowercase
Ucfirst	PHP4,PHP5	Converts the first letter of a string to uppercase
Lcfirst	php5>= 5.3.0	Converts the first letter of a string to lowercase
Ucwords	PHP4,PHP5	Converts the first character of each word in a string to uppercase
Mb_strtoupper	php4>=4.3.0,php 5	Convert a string to uppercase (different from the strtoupper function)
Mb_strtolower	php4>=4.3.0,php 5	Convert a string to lowercase (different from the strtolower function)
Mb_convert_case	php4>=4.3.0,php 5	Convert strings according to different patterns

PHP provides a function for case-sensitive conversions
Array_change_key_case (Array,case)
Array required. Specifies the array to use.
Case Case_lower-default value, lowercase; case_upper uppercase.
Example:

$arr = Array (' ID ' = = 1, ' NAME ' = ' Yami ', ' Con ' = ' = ' = ' PHONE ' = ' = ' 123456 ', ' email ' = ' = ' [email protected] ' ));p Rint_r (Array_change_key_case ($arr, case_lower));

Unfortunately, this method can only implement conversion of one-dimensional arrays.
Here's a function to transform a multidimensional array.

/* * Convert array key value case * * @author    yamiliu<[email protected]> * @params    $aValue    array required to convert * @params 
    $case    boolean  0: lowercase, default, 1: Uppercase *  */function Changearrkey (& $aValue, $case = 0) {    foreach ($aValue as $key = = $item) {        if ($case) {            $keyTemp = Strtoupper ($key);        } else {            $keyTemp = Strtolower ($key); c13/>}         if ($keyTemp! = $key) {            unset ($aValue [$key]);            $aValue [$keyTemp] = $item;        }        if (Is_array ($item)) {            Changearrkey ($aValue [$keyTemp], $case);}}}    Call $arr = Array (' ID ' = = 1, ' NAME ' = ' = ' Yami ', ' Con ' = ' = ' = ' PHONE ' = ' = ' 123456 ', ' email ' = ' [email protec Ted]); Changearrkey ($arr); Var_dump ($arr);

Later think about changing the value of the original array is not a good note
Another way to write it is as follows:

/* * @author    yamiliu<[email protected]> * @params array   $aValue    required to convert * @params    Boolean $ Case      0: lowercase, default, 1: Uppercase * @return              array converted arrays  */function array_key_to_case ($aValue, $case = 0) {    $ avaluetemp = Array ();    foreach ($aValue as $key = + $item) {        if ($case) {            $keyTemp = Strtoupper ($key);        } else {            $keyTem p = strtolower ($key);        }        $aValueTemp [$keyTemp] = $item;        if (Is_array ($item)) {            $aValueTemp [$keyTemp] = Array_key_to_case ($item, $case);        }    }    return $aValueTemp;} Call $arr = array (' id ' = = 1, ' name ' = ' = ' Yami ', ' Con ' = ' = ' = ' phone ' = ' = ' 123456 ', ' email ' = ' [email protec Ted]); $r   = Array_key_to_case ($arr, 1);p Rint_r ($r);

PHP String Case Conversion