CascadiaPHP 2024

数组

  • 简介
  • 安装/配置
  • 预定义常量
  • 对数组进行排序
  • 数组 函数
    • array_change_key_case — 将数组中的所有键名修改为全大写或小写
    • array_chunk — 将一个数组分割成多个
    • array_column — 返回输入数组中指定列的值
    • array_combine — 创建一个数组,用一个数组的值作为其键名,另一个数组的值作为其值
    • array_count_values — 统计数组中每个不同值的出现次数
    • array_diff_assoc — 带索引检查计算数组的差集
    • array_diff_key — 使用键名比较计算数组的差集
    • array_diff_uassoc — 用用户提供的回调函数做索引检查来计算数组的差集
    • array_diff_ukey — 用回调函数对键名比较计算数组的差集
    • array_diff — 计算数组的差集
    • array_fill_keys — 使用指定的键和值填充数组
    • array_fill — 用给定的值填充数组
    • array_filter — 使用回调函数过滤数组的元素
    • array_flip — 交换数组中的键和值
    • array_intersect_assoc — 带索引检查计算数组的交集
    • array_intersect_key — 使用键名比较计算数组的交集
    • array_intersect_uassoc — 带索引检查计算数组的交集,用回调函数比较索引
    • array_intersect_ukey — 在键名上使用回调函数来比较计算数组的交集
    • array_intersect — 计算数组的交集
    • array_is_list — 判断给定的 array 是否为 list
    • array_key_exists — 检查数组里是否有指定的键名或索引
    • array_key_first — 获取指定数组的第一个键
    • array_key_last — 获取一个数组的最后一个键值
    • array_keys — 返回数组中部分的或所有的键名
    • array_map — 为数组的每个元素应用回调函数
    • array_merge_recursive — 递归地合并一个或多个数组
    • array_merge — 合并一个或多个数组
    • array_multisort — 对多个数组或多维数组进行排序
    • array_pad — 以指定长度将一个值填充进数组
    • array_pop — 弹出数组最后一个单元(出栈)
    • array_product — 计算数组中所有值的乘积
    • array_push — 将一个或多个单元压入数组的末尾(入栈)
    • array_rand — 从数组中随机取出一个或多个随机键
    • array_reduce — 用回调函数迭代地将数组简化为单一的值
    • array_replace_recursive — 使用传递的数组递归替换第一个数组的元素
    • array_replace — 使用传递的数组替换第一个数组的元素
    • array_reverse — 返回单元顺序相反的数组
    • array_search — 在数组中搜索给定的值,如果成功则返回首个相应的键名
    • array_shift — 将数组开头的单元移出数组
    • array_slice — 从数组中取出一段
    • array_splice — 去掉数组中的某一部分并用其它值取代
    • array_sum — 对数组中所有值求和
    • array_udiff_assoc — 带索引检查计算数组的差集,用回调函数比较数据
    • array_udiff_uassoc — 带索引检查计算数组的差集,用回调函数比较数据和索引
    • array_udiff — 用回调函数比较数据来计算数组的差集
    • array_uintersect_assoc — 带索引检查计算数组的交集,用回调函数比较数据
    • array_uintersect_uassoc — 带索引检查计算数组的交集,用单独的回调函数比较数据和索引
    • array_uintersect — 计算数组的交集,用回调函数比较数据
    • array_unique — 移除数组中重复的值
    • array_unshift — 在数组开头插入一个或多个单元
    • array_values — 返回数组中所有的值
    • array_walk_recursive — 对数组中的每个成员递归地应用用户函数
    • array_walk — 使用用户自定义函数对数组中的每个元素做回调处理
    • array — 新建一个数组
    • arsort — 对数组进行降向排序并保持索引关系
    • asort — 对数组进行升序排序并保持索引关系
    • compact — 建立一个数组,包括变量名和它们的值
    • count — 统计数组、Countable 对象中所有元素的数量
    • current — 返回数组中的当前值
    • each — 返回数组中当前的键/值对并将数组指针向前移动一步
    • end — 将数组的内部指针指向最后一个单元
    • extract — 从数组中将变量导入到当前的符号表
    • in_array — 检查数组中是否存在某个值
    • key_exists — 别名 array_key_exists
    • key — 从关联数组中取得键名
    • krsort — 对数组按照键名逆向排序
    • ksort — 对数组根据键名升序排序
    • list — 把数组中的值赋给一组变量
    • natcasesort — 用“自然排序”算法对数组进行不区分大小写字母的排序
    • natsort — 用“自然排序”算法对数组排序
    • next — 将数组中的内部指针向前移动一位
    • pos — current 的别名
    • prev — 将数组的内部指针倒回一位
    • range — 根据范围创建数组,包含指定的元素
    • reset — 将数组的内部指针指向第一个单元
    • rsort — 对数组降序排序
    • shuffle — 打乱数组
    • sizeof — count 的别名
    • sort — 对数组升序排序
    • uasort — 使用用户定义的比较函数对数组进行排序并保持索引关联
    • uksort — 使用用户自定义的比较函数对数组中的键名进行排序
    • usort — 使用用户自定义的比较函数对数组中的值进行排序
add a note

User Contributed Notes 17 notes

up
107
applegrew at rediffmail dot com
16 years ago
For newbies like me.

Creating new arrays:-
//Creates a blank array.
$theVariable = array();

//Creates an array with elements.
$theVariable = array("A", "B", "C");

//Creating Associaive array.
$theVariable = array(1 => "http//google.com", 2=> "http://yahoo.com");

//Creating Associaive array with named keys
$theVariable = array("google" => "http//google.com", "yahoo"=> "http://yahoo.com");

Note:
New value can be added to the array as shown below.
$theVariable[] = "D";
$theVariable[] = "E";
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20
Tyler Bannister
15 years ago
To delete an individual array element use the unset function

For example:

<?PHP
$arr
= array( "A", "B", "C" );
unset(
$arr[1] );
// now $arr = array( "A", "C" );
?>

Unlink is for deleting files.
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6
macnimble at gmail dot com
15 years ago
Converting a linear array (like a mysql record set) into a tree, or multi-dimensional array can be a real bugbear. Capitalizing on references in PHP, we can 'stack' an array in one pass, using one loop, like this:

<?php
# array_stack()
# Original idea from:
# http://www.ideashower.com/our_solutions/
# create-a-parent-child-array-structure-in-one-pass/
function array_stack (&$a, $p = '@parent', $c = '@children')
{
$l = $t = array();
foreach (
$a AS $key => $val):
if (!
$val[$p]) $t[$key] =& $l[$key];
else
$l[$val[$p]][$c][$key] =& $l[$key];
$l[$key] = (array)$l[$key] + $val;
endforeach;
return
$a = array('tree' => $t, 'leaf' => $l);
}

# Example:
$node = array();
$node[1] = array('@parent' => 0, 'title' => 'I am node 1.');
# ^-----------------------v Link @parent value to key.
$node[2] = array('@parent' => 1, 'title' => 'I am node 2.');
$node[3] = array('@parent' => 2, 'title' => 'I am node 3.');
$node[4] = array('@parent' => 1, 'title' => 'I am node 4.');
$node[5] = array('@parent' => 4, 'title' => 'I am node 5.');

array_stack($node);

$node['leaf'][1]['title'] = 'I am node one.';
$node['leaf'][2]['title'] = 'I am node two.';
$node['leaf'][3]['title'] = 'I am node three.';
$node['leaf'][4]['title'] = 'I am node four.';
$node['leaf'][5]['title'] = 'I am node five.';

echo
'<pre>',print_r($node['tree'],TRUE),'</pre>';
?>

Note that there's no parameter checking on the array value, but this is only to keep the function size small. One could easily a quick check in there to make sure the $a parameter was in fact an array.

Hope you find it useful. Huge thanks to Nate Weiner of IdeaShower.com for providing the original function I built on.
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2
webmaster at infoproducts dot x10hosting dot com
15 years ago
New value can also be added to the array as shown below.
$theVariable["google"] = "http//google.com";
or
$theVariable["1"] = "http//google.com";
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2
dragos dot rusu at NOSPAM dot bytex dot ro
14 years ago
If an array item is declared with key as NULL, array key will automatically be converted to empty string '', as follows:

<?php
$a
= array(
NULL => 'zero',
1 => 'one',
2 => 'two');

// This will show empty string for key associated with "zero" value
var_dump(array_keys($a));

// Array elements are shown
reset($a);
while(
key($a) !== NULL )
{
echo
key($a) . ": ".current($a) . "<br>";// PHP_EOL
next($a);
}

// Array elements are not shown
reset($a);
while(
key($a) != NULL ) // '' == null => no iteration will be executed
{
echo
key($a) . ": ".current($a) . "<br>";// PHP_EOL
next($a);
}
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-1
andyd273 at gmail dot com
15 years ago
A small correction to Endel Dreyer's PHP array to javascript array function. I just changed it to show keys correctly:

function array2js($array,$show_keys)
{
$dimensoes = array();
$valores = array();

$total = count ($array)-1;
$i=0;
foreach($array as $key=>$value){
if (is_array($value)) {
$dimensoes[$i] = array2js($value,$show_keys);
if ($show_keys) $dimensoes[$i] = '"'.$key.'":'.$dimensoes[$i];
} else {
$dimensoes[$i] = '"'.addslashes($value).'"';
if ($show_keys) $dimensoes[$i] = '"'.$key.'":'.$dimensoes[$i];
}
if ($i==0) $dimensoes[$i] = '{'.$dimensoes[$i];
if ($i==$total) $dimensoes[$i].= '}';
$i++;
}
return implode(',',$dimensoes);
}
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-1
sunear at gmail dot com
14 years ago
Made this function to delete elements in an array;

<?php

function array_del_elm($input_array, $del_indexes) {
if (
is_array($del_indexes)) {
$indexes = $del_indexes;
} elseif(
is_string($del_indexes)) {
$indexes = explode($del_indexes, " ");
} elseif(
is_numeric($del_indexes)) {
$indexes[0] = (integer)$del_indexes;
} else return;
$del_indexes = null;

$cur_index = 0;
if (
sort($indexes)) for($i=0; $i<count($input_array); $i++) {
if (
$i == $indexes[$cur_index]) {
$cur_index++;
if (
$cur_index == count($indexes)) return $output_array;
continue;
}
$output_array[] = $input_array[$i];
}
return
$output_array;
}

?>

but then i saw the methods of doing the same by Tyler Bannister & Paul, could see that theirs were faster, but had floors regarding deleting multiple elements thus support of several ways of giving parameters. I combined the two methods to this to this:

<?php

function array_del_elm($target_array, $del_indexes) {
if (
is_array($del_indexes)) {
$indexes = $del_indexes;
} elseif(
is_string($del_indexes)) {
$indexes = explode($del_indexes, " ");
} elseif(
is_numeric($del_indexes)) {
$indexes[0] = (integer)$del_indexes;
} else return;
unset(
$del_indexes);

for(
$i=0; $i<count($indexes); $i++) {
unset(
$target_array[$indexes[$i]]);
}
return
$target_array;
}

?>

Fast, compliant and functional ;)
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-4
web at houhejie dot cn
6 years ago
string2array($str):

$arr=json_decode('["fileno",["uid","uname"],"topingid",["touid",[1,2,[3,4]],"touname"]]');
print_r($arr);

output:
Array ( [0] => fileno [1] => Array ( [0] => uid [1] => uname ) [2] => topingid [3] => Array ( [0] => touid [1] => Array ( [0] => 1 [1] => 2 [2] => Array ( [0] => 3 [1] => 4 ) ) [2] => touname ) )

when I hope a function string2array($str), "spam2" suggest this. and It works well~~~hope this helps us, and add to the Array function list
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-4
justin at jmfrazier dot com
4 years ago
Using null as the key when setting an array value is NOT the same as using empty [].
<?php
$null
= null;
$testArray = [];
$testArray[$null] = 1;
$testArray[$null] = 2;
$testArray[$null] = 3;
$testArray[$null] = 4;
var_dump($testArray);
?>
Output:
array(1) {
'' =>
int(4)
}

<?php
$testArray
= [];
$testArray[null] = 1;
$testArray[null] = 2;
$testArray[null] = 3;
$testArray[null] = 4;
var_dump($testArray);
?>
Output:
array(1) {
'' =>
int(4)
}

<?php
$testArray
= [];
$testArray[] = 1;
$testArray[] = 2;
$testArray[] = 3;
$testArray[] = 4;
var_dump($testArray);
?>
Output:
array(4) {
[0] =>
int(1)
[1] =>
int(2)
[2] =>
int(3)
[3] =>
int(4)
}
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-4
info at curtinsNOSPAMcreations dot com
13 years ago
Another way to create a multidimensional array that looks a lot cleaner is to use json_decode. (Note that this probably adds a touch of overhead, but it sure does look nicer.) You can of course add as many levels and as much formatting as you'd like to the string you then decode. Don't forget that json requires " around values, not '!! (So, you can't enclose the json string with " and use ' inside the string.)

As an example:

<?php
$myarray
['blah'] = json_decode('[
{"label":"foo","name":"baz"},
{"label":"boop","name":"beep"}
]'
,true);

print_r($myarray)
?>
returns:

Array
(
[blah] => Array
(
[0] => Array
(
[label] => foo
[name] => baz
)

[1] => Array
(
[label] => boop
[name] => beep
)
)
)
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-6
contact at greyphoenix dot biz
16 years ago
<?php
//Creating a multidimensional array

$theVariable = array("Search Engines" =>
array (
0=> "http//google.com",
1=> "http//yahoo.com",
2=> "http//msn.com/"),

"Social Networking Sites" =>
array (
0 => "http//www.facebook.com",
1 => "http//www.myspace.com",
2 => "http//vkontakte.ru",)
);

echo
"The first array value is " . $theVariable['Search Engines'][0];
?>

-- Output--
The first array value is http://google.com
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-7
Anonymous
15 years ago
@jorge at andrade dot cl
This variant is faster:
<?php
function array_avg($array,$precision=2){
if(!
is_array($array))
return
'ERROR in function array_avg(): this is a not array';

foreach(
$array as $value)
if(!
is_numeric($value))
return
'ERROR in function array_avg(): the array contains one or more non-numeric values';

$cuantos=count($array);
return
round(array_sum($array)/$cuantos,$precision);
}
?>
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-7
spereversev at envionsoftware dot com
12 years ago
<?php
function array_mask(array $array, array $keys) {
return
array_intersect_key( $array, array_fill_keys( $keys, 0 ) );
}
?>

Might be helpful to take a part of associative array containing given keys, for example, from a $_REQUEST array

array_mask($_REQUEST, array('name', 'email'));
up
-7
gratcypalma at gmail dot com
10 years ago
<?php
function foo() {
return array(
'name' => 'palma', 'old' => 23, 'language' => 'PHP');
}
/* 1. PHP < 5.4.0 */
$a = foo();
var_dump($a['name']);

/* 2. Works ini PHP >= 5.4.0 */

var_dump(foo()['name']);

/*
When i run second method on PHP 5.3.8 i will be show error message "PHP Fatal error: Can't use method return value in write context"

http://www.php.net/manual/en/migration54.new-features.php
*/
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-8
thomasdecaux at ebuildy dot com
15 years ago
To browse a simple array:

<?php

foreach ($myArray AS $myItem)
{

}

?>

To browse an associative array:

<?php

foreach ($myArray AS $key=>$value)
{

}

?>

http://www.ebuildy.com
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-19
Jack A
15 years ago
Note that arrays are not allowed in class constants and trying to do so will throw a fatal error.
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-24
John Marc
14 years ago
Be careful when adding elements to a numeric array.
I wanted to store some info about some items from a database and decided to use the record id as a key.

<?php
$key
=3000000000;
$DATA[$key]=true;
?>

This will create an array of 30 million elements and chances are, you will use up all memory with these 2 lines

<?php
$key
=3000000000;
$DATA["$key"]=true;
?>

This on the other hand will force the array to be an associative array and will only create the one element
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