array("1" => "百度","2" => "阿里","3" => "腾讯");
或者是不使用键值：
array("百度","阿里","腾讯");
当然也可以写成：
$arr[0] = "百度";
$arr[1] = "阿里";
$arr[2] = "腾讯";

<?php
$arr = array("百度","阿里","腾讯");
echo count($arr);
?> //结果返回3（说明数组中有三个元素）

<?php
$arr = array("百度","阿里","腾讯");
$arrlen = count($arr);//获取数组的长度
for ($i=0; $i <$arrlen ; $i++) { 
  $data[] = $arr[$i]; 
}
echo "<pre>"; //换行显示
print_r($data);

<?php
$arr = array("百度","阿里","腾讯");
foreach ($arr as $value) {
  $data[] = $value;
}
echo "<pre>"; //换行显示
print_r($data);//打印结果和上面一样

<?php
$arr = array("李彦宏" => "百度","马云" => "阿里","马化腾" => "腾讯");
foreach ($arr as $key => $value) {
  $data[$key] = $value;
}
echo "<pre>"; //换行显示
print_r($data);

Array
(
  [李彦宏] => 百度
  [马云] => 阿里
  [马化腾] => 腾讯
)

<?php
$arr = array("百度","阿里","腾讯");
array_push($arr,"知乎","微博");
echo "<pre>"; //换行显示
print_r($arr);
//打印结果显示：
Array
(
  [0] => 百度
  [1] => 阿里
  [2] => 腾讯
  [3] => 知乎
  [4] => 微博
)

<?php
$arr = array("百度","阿里","腾讯");
array_unshift($arr,"知乎","微博");
echo "<pre>"; //换行显示
print_r($arr);
//打印结果显示：
Array
(
  [0] => 知乎
  [1] => 微博
  [2] => 百度
  [3] => 阿里
  [4] => 腾讯
)

<?php
$arr = array("百度","阿里","腾讯");
array_pop($arr);
echo "<pre>"; //换行显示
print_r($arr);
打印结果显示：
Array
(
  [0] => 百度
  [1] => 阿里
)

<?php
$arr = array("百度","阿里","腾讯");
array_shift($arr);
echo "<pre>"; //换行显示
print_r($arr);
打印结果显示：
Array
(
  [0] => 阿里
  [1] => 腾讯
)

<?php
$arr = array("百度","阿里","腾讯","百度","微博");
$data = array_unique($arr);
echo "<pre>";
print_r($data);
打印结果显示：
Array
(
  [0] => 百度
  [1] => 阿里
  [2] => 腾讯
  [4] => 微博
)

<?php
$arr = array("百度","阿里","腾讯");
while (in_array("百度", $arr)) {
  echo "已经找到";
  break;
} //输出已经找到

<?php
$arr = array("百度","阿里","腾讯","知乎","微博");
$data = array_slice($arr,0,4);
echo "<pre>";
print_r($data);
打印结果显示：
Array
(
  [0] => 百度
  [1] => 阿里
  [2] => 腾讯
  [3] => 知乎
)

<?php
$arr1 = array("百度","阿里","腾讯");
$arr2 = array("知乎","微博");
array_splice($arr1,0,2,$arr2);
echo "<pre>";
print_r($arr1);
打印结果显示：
Array
(
  [0] => 知乎
  [1] => 微博
  [2] => 腾讯
)

<?php
$arr1 = array("百度","阿里","腾讯");
$arr2 = array("知乎","微博");
$data = array_merge($arr1,$arr2);
echo "<pre>";
print_r($data);
打印结果显示：
Array
(
  [0] => 百度
  [1] => 阿里
  [2] => 腾讯
  [3] => 知乎
  [4] => 微博
)

$arr= array('one'=>'C', 'one'=>'B'); 
$arr1= array('three'=>'1', 'one'=>'2'); 
$arr2= array_merge_recursive($arr, $arr1); 
echo "<pre>";
print_r($arr2); 
打印结果显示：
Array
(
  [one] => Array
    (
      [0] => B
      [1] => 2
    )

  [three] => 1
)

$arr= array('A', 'B'); 
$arr1= array('1', '2'); 
$arr2= array_combine($arr, $arr1);
echo "<pre>";
print_r($arr2); 
打印结果显示：
Array
(
  [A] => 1
  [B] => 2
)

$arr= array('A', 'B', 'C', 'D'); 
$arr1= array('A', 'B', 'E'); 
$arr2= array('A', 'F', 'D'); 
$arr3= array_intersect($arr, $arr1, $arr2); 
echo "<pre>";
print_r($arr3); 
打印结果显示：
Array
(
  [0] => A
)

$arr= array('a'=>'A', 'b'=>'B', 'c'=>'C', 'd'=>'D'); 
$arr1= array('a'=>'A', 'c'=>'B', 'E'); 
$arr2= array('a'=>'A', 'b'=>'F', 'd'=>'B'); 
$arr3= array_intersect_assoc($arr, $arr1, $arr2); 
echo "<pre>";
print_r($arr3); 
打印结果显示：
Array
(
  [a] => A
)

$arr= array('a'=>'A', 'b'=>'B', 'c'=>'C', 'd'=>'D'); 
$arr1= array('a'=>'A', 'b'=>'B', 'e'=>'E'); 
$arr3= array_diff_assoc($arr, $arr1); 
echo "<pre>";
print_r($arr3); 
打印结果显示：
Array
(
  [c] => C
  [d] => D
)

$arr= array('a'=>'A', 'b'=>'B', 'c'=>'C', 'd'=>'D'); 
$arr1= array_rand($arr, 2); 
echo "<pre>";
print_r($arr1);
打印结果显示：
 Array
(
  [0] => c
  [1] => d
) //每次刷新显示的结果都不一样

$arr= array('A', 32, 12, 'B'); 
$count= array_sum($arr); 
echo "<pre>";
print_r($count); 

$arr= array('A', 'B', 'C', 'D'); 
$arr1= array_chunk($arr, 2); 
echo "<pre>";
print_r($arr1); 

Array
(
  [0] => Array
    (
      [0] => A
      [1] => B
    )

  [1] => Array
    (
      [0] => C
      [1] => D
    )

)

array_filter(*array*,*callbackfunction*);
array_intersect_uassoc(*array1*,*array2*,*array3*...,*myfunction*)
array_intersect_ukey(*array1*,*array2*,*array3*...,*myfunction*)
array_reduce(*array*,*myfunction*,*initial*)
array_walk(*array*,*myfunction*,*userdata*...)
……