//定义回调函数 function key_compare_func($key1,$key2) {   if($key1==$key2)         //如果两参数相等   return 0;          //返回0   else if($key1>$key2)        //如果$key1>$key2   return 1;          //返回1   else           //如果$key1<$key2   return -1;          //返回-1 } //分别定义两个数组 $array1=array('blue'=>1,'red'=>2,'green'=>3,'purple'=>4); $array2=array('green'=>5,'blue'=>6,'yellow'=>7,'cyan'=>8); //用回调函数对键名比较计算数组的差集 $result=var_dump(array_diff_ukey($array1,$array2,'key_compare_func')); print_r($result); //输出比较结果          $array1=array("a"=>"green","red","blue","red");     //定义数组1 $array2=array("b"=>"green","yellow","red");     //定义数组2 $result=array_diff($array1,$array2);       //计算差集 print_r($result);           //输出比较结果 // $result=array_fill(5,6,'banana');    //为数组$a从第5个元素开始添加6个banana print_r($result);       //输出结果 // function odd($var) {   return($var%2==1);     //如果参数为奇数，返回true，否则返回false } function even($var) {   return($var%2==0);     //如果参数为偶数，返回true，否则返回false } //分别定义两个数组 $array1=array("a"=>1,"b"=>2,"c"=>3,"d"=>4,"e"=>5); $array2=array(6,7,8,9,10,11,12); echo "过滤奇数:n"; print_r(array_filter($array1,"odd"));   //过滤数组1中的奇数 echo "过滤偶数:n"; print_r(array_filter($array2,"even"));   //过滤数组2中的偶数 // $trans=array("a"=>1,"b"=>2,"c"=>3);     //定义数组 $result=array_flip($trans);       //反转数组 print_r($result);         //输出反转后的数组 // $array1=array("a"=>"green","b"=>"brown","c"=>"blue","red"); $array2=array("a"=>"green","yellow","red"); $result_array=array_intersect_assoc($array1,$array2);  //交集赋值到$result_array print_r($result_array);        //输出结果数组