Applies the user-defined function
function to each element of the array array. Typically, function takes on two parameters. The
array parameter's value
being the first, and the key/index second. If the optional
userdata parameter is
supplied, it will be passed as the third parameter to the
callback function.
If function function
requires more parameters than given to it, an error of level
E_WARNING will be generated each time array_walk() calls
function. These warnings may be suppressed by
prepending the PHP error operator @ to the array_walk() call, or by using
error_reporting().
注: If function needs to be working with the actual values of the array, specify the first parameter of function as a reference. Then, any changes made to those elements will be made in the original array itself.
注: Passing the key and userdata to function was added in 4.0.0
array_walk() is not affected by
the internal array pointer of
array.
array_walk() will
walk through the entire array regardless of pointer position.
To reset the pointer, use reset(). In PHP 3, array_walk() resets the pointer.
Users may not change the array itself from the callback
function. e.g. Add/delete elements, unset elements, etc. If
the array that array_walk() is
applied to is changed, the behavior of this function is
undefined, and unpredictable.
See also list(), foreach, each(), and
call_user_func_array().