The natsort() function is used to sorts an array using a "natural order" algorithm. The function implements a sort algorithm but maintains original keys/values.This function implements a sort algorithm that orders alphanumeric strings in the way a human being would while maintaining key/value associations.This function implements a sort algorithm that orders alphanumeric strings in the way a human being would while maintaining key/value associations. This is described as a "natural ordering". An example of the difference between this algorithm and the regular computer string sorting algorithms (used in sort()) can be seen in the example below.