array_replace_recursive replaces the values of array with the same values from all the following arrays. If a key from the first array exists in the second array, its value will be replaced by the value from the second array. If the key exists in the second array, and not the first, it will be created in the first array. If a key only exists in the first array, it will be left as is. If several arrays are passed for replacement, they will be processed in order, the later array overwriting the previous values.
array_replace_recursive is recursive : it will recurse into arrays and apply the same process to the inner value.
When the value in the first array is scalar, it will be replaced by the value in the second array, may it be scalar or array. When the value in the first array and the second array are both arrays, array_replace_recursive will replace their respective value recursively.
The array in which elements are replaced.
Arrays from which elements will be extracted.
Returns an array, or null if an error occurs.