PHP Basics Summary--arrays

Indexed array: An array with a numeric index

Initializing an array

$arr Array (' value1 ', ' value2 ', ' value3 ');　　$arr = [' value1 ', ' value2 ', ' value3 ']; /* PHP5.4 version starts to support */

Iterating through an array

For loop traversal:

 for ($i$i<count($arr$i+ +)    {echo$ Arr[$i]. ' ';}

foreach Loop traversal:

foreach ($arras$value) {    echo$value. ' ';}

Array sorting

Sort　　　　($arr) /* sort the indexed array in ascending order */ Rsort　　　　($arr) /* sort the indexed array in descending order */ /* when these two functions are used for associative arrays, the key values are ignored to sort the associative array into an indexed array */

Associative arrays: Arrays of custom key values

Initializing an array

$arr Array (' key1 ' = ' value1 ', ' key2 ' = ' value2 ', ' key3 ' = ' value3 ');　　$arr = [' key1 ' = ' value1 ', ' key2 ' = ' value2 ', ' Key3 ' and ' value3 ']; /* PHP5.4 version starts to support */

Iterating through an array

An indexed array cannot be traversed with a for loop (no numeric index exists), but it can still be used with foreach:

foreach ($arras$key= +$value) {  echo$key. ' = '. $value. " ;}

There is also a cool way to traverse:

 while (list($key,$valueeach ($arr)) {    echo$key . ' = '. $value. " ;}

Array sorting

Asort($arr);/*sorts in ascending order based on the values of the array. */Ksort($arr);/*Sort Ascending by the keys of the array. */Arsort($arr);/*sorts in descending order based on the values of the array. */Krsort($arr);/*sorts the keys of the array in descending order. */  /*Ksort (), Aksort () Two functions are not valid for indexed arrays, Asort (), Arsort () two functions are equivalent to sort (), Rsort () for an indexed array*/

Array Common functions

Count();/*returns the array length (number of elements)*/ Array_pop();/*Delete the last element of the array (out of the stack)*/ Array_push();/*inserts one or more elements into the end of an array (into the stack)*/Array_merge();/*combine one or more arrays into an array*/Array_unique();/*Remove the same element from the array*/In_array();/*detects if a value is in an array (returns True and false)*/Shuffle();/*disturb the original array*/...

PHP Basics Summary--arrays