PHP数组的一些常用函数

2---数组中键名的返回---------->array_keys();

//这两个函数的返回值也同样是数组,下表改变为索引,从0开始

'lumia800','brand2'=>'lumia900','brand3'=>'lumia640xl');    echo "
";    var_dump(array_values($arr));    echo "
";        echo "
";        echo "
";    var_dump(array_keys($arr));    echo "
";

//程序的结果如下1,2

array(3) {  [0]=>  string(8) "lumia800"  [1]=>  string(8) "lumia900"  [2]=>  string(10) "lumia640xl"}

array(3) {  [0]=>  string(6) "brand1"  [1]=>  string(6) "brand2"  [2]=>  string(6) "brand3"}

//***************************************************************************************************************

3---检查数组中是否存在某个元素---------->in_array(needle,haystach,[boll strict]);

输出**************************************//boolean true//boolean true//boolean false<-------因为第三个参数表示为严格查找--->类型和值?>

3---数组元素键名与值得对调

 "php",           "lang2" => "python",           "lang3" => "node");var_dump(array_flip($arr));//**********************//'php' => string 'lang1' (length=5)//'python' => string 'lang2' (length=5)//'node' => string 'lang3' (length=5)?>

4：数组元素个数的统计---count()

array("php5.3","php5.4","php5.5","php7"),              "python" =>array("python2.7","python3.3","python3.4")            );$num1 = count($arr1);    //遍历到一维 php+python=2$num2 = count($arr1,1);  //一维+二维遍历 2+4+3=9echo '数组$arr1一维统计的结果是-'.$num1."
";echo '数组$arr1多维统计的结果是-'.$num2."
";?>

5：数组中元素出现次数的统计array_count_values()

 int 2 //  1 => int 3 //  'python' => int 1?>

6：删除数组中重复的值array_unique()

"php","b"=>1,"c"=>"python","d"=>1,"e"=>"php",1);var_dump(array_unique($arr));//********如有值重复则保留前面的删除后面的*******  // 'a' => string 'php' (length=3)  // 'b' => int 1  // 'c' => string 'python' (length=6)?>

7：调用自定义的函数处理数组内容array_filter()

输出结果***********************  // 0 => int 1  // 2 => int 3  // 4 => int 5  // 6 => int 7  // 8 => int 9?>

8：数组元素值得排序

 string 'A' (length=1)----->大写最小  // 1 => string 'a' (length=1)----->小写次之  // 2 => string 'b' (length=1)  // 3 => string 'g' (length=1)  // 4 => int 1--------------------->数字最大了  // 5 => int 2  // 6 => int 3  // 7 => int 4  // 8 => int 6rsort($arr);var_dump($arr);  //倒序---从大到小//   0 => int 6//   1 => int 4//   2 => int 3//   3 => int 2//   4 => int 1?>

9: 根据条件在数组取出一段值并返回---array_slice()

10: 数组的合并为一个新数组，前数组键名，后数组键值

 string 'linux' (length=5)  // 'webserver' => string 'apache' (length=6)  // 'database' => string 'mongodb' (length=7)  // 'script' => string 'php' (length=3)?>

11：数组的合并，有相同元素值的保留后一个array_merge()

'windows','b'=>'apache','c'=>'mysql');$arr2=array('d'=>'linux','b'=>'nginx','e'=>'mongodb');//数组的合并,若两数组中有相同的键名则后面覆盖前面var_dump(array_merge($arr1, $arr2));  // 'a' => string 'windows' (length=7)  // 'b' => string 'nginx' (length=5)  // 'c' => string 'mysql' (length=5)  // 'd' => string 'linux' (length=5)  // 'e' => string 'mongodb' (length=7)?>

12: 数组的交集与差集array_intersect()与array_diff()

 string 'windows' (length=7)//   2 => string 'mysql' (length=5)?>

13: 数组内容的追加--array_push()

 string 'windows' (length=7)  // 1 => string 'nginx' (length=5)  // 2 => string 'mysql' (length=5)  // 3 => string 'php' (length=3)var_dump($arr2);  // 0 => string 'linux' (length=5)  // 1 => string 'nginx' (length=5)  // 2 => string 'mongodb' (length=7)  // 3 =>   //   array  //     0 => string 'windows' (length=7)  //     1 => string 'nginx' (length=5)  //     2 => string 'mysql' (length=5)  //     3 => string 'php' (length=3)?>

14:数组元素由后往前删除array_pop()

 string 'linux' (length=5)//   1 => string 'apache' (length=6)//   2 => string 'ngnix' (length=5)//*********************************// array//   0 => string 'linux' (length=5)//   1 => string 'apache' (length=6)?>

15:数组元素由前往后删除array_pop()

 string 'apache' (length=6)//   1 => string 'ngnix' (length=5)//   2 => string 'php' (length=3)// array//   0 => string 'ngnix' (length=5)//   1 => string 'php' (length=3)?>