Distinguish sort function

<?php
1.sort () indexed array sorted alphabetically by value
$fruits = Array ("Lemon", "orange", "banana", "apple");
Sort ($fruits);
foreach ($fruits as $key = = $val) {
echo "fruits[". $key. "] = " . $val. "\ n";
}
Echo ' 2.asort () (note: associative, indexed) arrays are sorted alphabetically by value
$fruits = Array ("d" = "lemon", "a" and "Orange", "b" = "banana", "c" = "apple");
Asort ($fruits);
foreach ($fruits as $key = = $val) {
echo "$key = $val \ n";
}

Echo '

Note: When an array is an indexed array, the sort results of using asort are the same as sort but the Asort index remains in the order before sorting
3.ksort () alphabetical ascending by index
$fruits = Array ("d" = "lemon", "a" and "Orange", "b" = "banana", "c" = "apple");
Ksort ($fruits);
foreach ($fruits as $key = = $val) {
echo "$key = $val \ n";
}
Array (' a ' = = ' orange ', ' b ' = ' banana ', ' c ' = ' apple ', ' d ' = ' lemon ');

Distinguish sort function