1.定義數(shù)組
<?php
$cars=array("Volvo","BMW","Toyota");
echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
?>
2.獲取數(shù)組長度
<?php
$cars=array("Volvo","BMW","Toyota");
echo count($cars);
?>
3.遍歷數(shù)組
<?php
$cars=array("Volvo","BMW","Toyota");
$arrlength=count($cars);
for($x=0;$x<$arrlength;$x++)
{
echo $cars[$x];
echo "<br>";
}
?>
4.關聯(lián)數(shù)組,類似map
key 可以是 integer 或者 string舶掖。value 可以是任意類型
1.包含有合法整型值的字符串會被轉(zhuǎn)換為整型。例如鍵名 "8" 實際會被儲存為 8善玫。
但是 "08" 則不會強制轉(zhuǎn)換，因為其不是一個合法的十進制數(shù)值焙畔。
2.浮點數(shù)也會被轉(zhuǎn)換為整型旷祸，意味著其小數(shù)部分會被舍去贡未。例如鍵名 8.7
實際會被儲存為 8。
3.布爾值也會被轉(zhuǎn)換成整型锚国。即鍵名 true 實際會被儲存為 1 而鍵名 false 會被儲存為 0
4.Null 會被轉(zhuǎn)換為空字符串腕巡，即鍵名 null 實際會被儲存為 ""。
5.數(shù)組和對象不能被用為鍵名血筑。堅持這么做會導致警告：Illegal offset type绘沉。
這里有兩種創(chuàng)建關聯(lián)數(shù)組的方法：
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
or:
$age['Peter']="35";
$age['Ben']="37";
$age['Joe']="43";
遍歷
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
// 自 PHP 5.4 起
$array = [ "foo" => "bar", "bar" => "foo",];
?>
5.多維數(shù)組
<?php
// 二維數(shù)組:
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
創(chuàng)建
<?php
$sites = array
(
"runoob"=>array
(
"菜鳥教程",
"http://www.runoob.com"
),
"google"=>array
(
"Google 搜索",
"http://www.google.com"
),
"taobao"=>array
(
"淘寶",
"http://www.taobao.com"
)
);
echo $sites['runoob'][0] . '地址為：' . $sites['runoob'][1];
?>
修改數(shù)組
<?php
$arr = array(5 => 1, 12 => 2);
$arr[] = 56; // This is the same as $arr[13] = 56;
// at this point of the script
$arr["x"] = 42; // This adds a new element to
// the array with key "x"
unset($arr[5]); // This removes the element from the array
unset($arr); // This deletes the whole array
?>
注意這里所使用的最大整數(shù)鍵名不一定當前就在數(shù)組中。它只要在上次數(shù)組重新生成索引后曾經(jīng)存在過就行了豺总。以下面的例子來說明：
<?php
// 創(chuàng)建一個簡單的數(shù)組
$array = array(1, 2, 3, 4, 5);
print_r($array);
// 現(xiàn)在刪除其中的所有元素车伞，但保持數(shù)組本身不變:
foreach ($array as $i => $value) {
unset($array[$i]);
}
print_r($array);
// 添加一個單元（注意新的鍵名是 5，而不是你可能以為的 0）
$array[] = 6;
print_r($array);
// 重新索引：
$array = array_values($array);
$array[] = 7;
print_r($array);
?>
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
)
Array
(
)
Array
(
[5] => 6
)
Array
(
[0] => 6
[1] => 7
)
數(shù)組函數(shù)
1.unset()
函數(shù)允許刪除數(shù)組中的某個鍵喻喳。但要注意數(shù)組將不會重建索引另玖。如果需要刪除后重建索引，可以用 array_values() 函數(shù)。
<?php
$a = array(1 => 'one', 2 => 'two', 3 => 'three');
unset($a[2]);
/* will produce an array that would have been defined as
$a = array(1 => 'one', 3 => 'three');
and NOT
$a = array(1 => 'one', 2 =>'three');
*/
$b = array_values($a);
// Now $b is array(0 => 'one', 1 =>'three')
?>
2.foreach 遍歷數(shù)組谦去，引用賦值
<?php
$arr = array(1, 2, 3, 4);
foreach ($arr as &$value) {
$value = $value * 2;
}
// $arr is now array(2, 4, 6, 8)
unset($value); // 最后取消掉引用
?>
更多例子
<?php
/* foreach example 1: value only */
$a = array(1, 2, 3, 17);
foreach ($a as $v) {
echo "Current value of \$a: $v.\n";
}
/* foreach example 2: value (with its manual access notation printed for illustration) */
$a = array(1, 2, 3, 17);
$i = 0; /* for illustrative purposes only */
foreach ($a as $v) {
echo "\$a[$i] => $v.\n";
$i++;
}
/* foreach example 3: key and value */
$a = array(
"one" => 1,
"two" => 2,
"three" => 3,
"seventeen" => 17
);
foreach ($a as $k => $v) {
echo "\$a[$k] => $v.\n";
}
/* foreach example 4: multi-dimensional arrays */
$a = array();
$a[0][0] = "a";
$a[0][1] = "b";
$a[1][0] = "y";
$a[1][1] = "z";
foreach ($a as $v1) {
foreach ($v1 as $v2) {
echo "$v2\n";
}
}
/* foreach example 5: dynamic arrays */
foreach (array(1, 2, 3, 4, 5) as $v) {
echo "$v\n";
}
?>
3.用 list() 給嵌套的數(shù)組解包
<?php
$array = [
[1, 2],
[3, 4],
];
foreach ($array as list($a, $b)) {
// $a contains the first element of the nested array,
// and $b contains the second element.
echo "A: $a; B: $b\n";
}
?>
//output
A: 1; B: 2
A: 3; B: 4
list() 中的單元可以少于嵌套數(shù)組的慷丽，此時多出來的數(shù)組單元將被忽略：
<?php
$array = [
[1, 2],
[3, 4],
];
foreach ($array as list($a)) {
// Note that there is no $b here.
echo "$a\n";
}
?>
//outout
1
3
4.排序
<?php
sort($files);
print_r($files);
?>
5.數(shù)組(Array) 的賦值總是會涉及到值的拷貝。使用引用運算符通過引用來拷貝數(shù)組鳄哭。
<?php
$arr1 = array(2, 3);
$arr2 = $arr1;
$arr2[] = 4; // $arr2 is changed,
// $arr1 is still array(2, 3)
$arr3 = &$arr1;
$arr3[] = 4; // now $arr1 and $arr3 are the same
?>
7.給數(shù)頭部添加元素：array_unshift();
<?php
$arr = array(1,2,3,4,5,6,7,8);
array_unshift($arr,8,9); //數(shù)組前面添加8,9
print_r($arr);?>
8. 給數(shù)組尾部添加元素：array_push();
<?php
$arr = array(1,2,3,4,5,6,7,8);
array_push($arr,8,9); //數(shù)組后面添加
print_r($arr);
?>
9.定義數(shù)組的長度添加元素：array_pad(array,定義數(shù)組長度,添加的值);
當定義數(shù)組長度大于數(shù)組本身長度時盈魁，在數(shù)組的尾部添加要添加的元素直至數(shù)組長度為定義的數(shù)組的長度；當數(shù)組定義長度等于或者小于數(shù)組本身的長度時窃诉，則不作操作；當數(shù)組定義的長度是負數(shù)且絕對值大于數(shù)組長度時赤套，則在數(shù)組的頭部添加元素飘痛，直至數(shù)組的長度為定義長度的絕對值長。
<?php
$arr = array(1,2,3,4,5,6,7,8);
$arr = array_pad($arr,10,10);
print_r($arr);//輸出數(shù)組
echo('<br/>'); //創(chuàng)建一個換行符
$arr = array_pad($arr,-15,-1);
print_r($arr); //輸出數(shù)組
?>
Paste_Image.png
10.刪除數(shù)組尾部的元素array_pop();
<?php
$arr = array(1,2,3,4,5,6,7,8); // 返回要刪除的元素容握，輸出已刪除元素后的數(shù)組
$a = array_pop($arr); //聲明變量a存放刪除的元素 echo($a); //輸出a
echo('<br/>'); //創(chuàng)建一個換行符
print_r($arr); //輸出數(shù)組arr
?>
11.刪除數(shù)組頭部的元素array_shift();
<?php
$arr = array(1,2,3,4,5,6,7,8);
// 刪除頭部數(shù)組元素
$a = array_shift($arr);
echo($a.'<br/>'); //輸出刪除的元素
print_r($arr); // 輸出刪除元素后的數(shù)組
?>
