PHP array _5_3_ array and its application handler function array pointer _3_

The following is learning Kong Xiangsheng editor of "PHP Programming Fundamentals tutorial and example" (second edition) notes made.

Function array pointer

1. key () function

program:

. 1 ? < PHP
 2  $ Interests [2] = "Music" ;
 . 3  $ Interests [. 5] = "Movie" ;
 . 4  $ Interests [. 1] = "Computer" ;
 . 5  $ Interests [] = "Software" ;
 . 6  var_dump ( key ( $ Interests ));   // int 2 // returns an array of arr "current pointer" within the meaning of the keys elements. 
7 ?>

Output:

D: \ wampServer \ www \ Apache Server home \ practice doing \ routine .php: 6: int 2

2. current () function

program:

. 1 ? < PHP
 2  $ Interests [2] = "Music" ;
 . 3  $ Interests [. 5] = "Movie" ;
 . 4  $ Interests [. 1] = "Computer" ;
 . 5  $ Interests [] = "Software" ;
 . 6  var_dump ( current ( $ Interests ));   // String 'Music' (length =. 5) // returns an array of arr "current pointer" refer to "value" elements 
7 >?

Output:

D: \ wampServer \ www \ Apache Server home \ practice doing \ routine .php:. 6: String 'Music' (length =. 5)

3. next () function

program:

 1 <?php
 2 $interests[2] = "music";
 3 $interests[5] = "movie";
 4 $interests[1] = "computer";
 5 $interests[] = "software";
 6 $second = next($interests);
 7 $third  = next($interests);
 8 var_dump(key($interests));  //int  1
 9 echo "<br/>";
10 var_dump(current($interests));  //string 'computer' (length=8)
11 echo "<br/>";
12 var_dump($second);  //string 'movie' (length=5)
13 echo "<br/>";
14 var_dump($third);   //string 'computer' (length=8)
15 ?>

Output:

D: \ wampServer \ www \ Apache Server home \ practice doing \ routine .php:. 8: int. 1 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php: 10: String 'Computer' (length . 8 = ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php: 12 is: String 'Movie' (length =. 5 ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine. PHP: 14: String 'Computer' (length =. 8)

4. end () function

program:

 1 <?php
 2 $interests[2] = "music";
 3 $interests[5] = "movie";
 4 $interests[1] = "computer";
 5 $interests[] = "software";
 6 $end = end($interests);
 7 var_dump(key($interests));      //int 6
 8 echo "<br/>";
 9 var_dump(current($interests));  //string 'software' (length=8)
10 echo "<br/>";
11 var_dump($end);                 //string 'software' (length=8)
12 ?>

Output:

D: \ wampServer \ www \ Apache Server home \ practice doing \ routine .php:. 7: int. 6 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php:. 9: String 'Software' (length . 8 = ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php:. 11: String 'Software' (length =. 8)

5. prev () function

program:

 1 <?php
 2 $interests[2] = "music";
 3 $interests[5] = "movie";
 4 $interests[1] = "computer";
 5 $interests[] = "software";
 6 $end = end($interests);
 7 $prev = prev($interests);
 8 var_dump(key($interests));  //int 1
 9 echo "<br/>";
10 var_dump(current($interests));  //string 'computer' (length=8)
11 echo "<br/>";
12 var_dump($end);     //string 'software' (length=8)
13 echo "<br/>";
14 var_dump($prev);    //string 'computer' (length=8)
15 ?>

Output:

D: \ wampServer \ www \ Apache Server home \ practice doing \ routine .php:. 8: int. 1 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php: 10: String 'Computer' (length . 8 = ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php: 12 is: String 'Software' (length. 8 = ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine. PHP: 14: String 'Computer' (length =. 8)

6. reset () function

program:

 1 <?php
 2 $interests[2] = "music";
 3 $interests[5] = "movie";
 4 $interests[1] = "computer";
 5 $interests[] = "software";
 6 $end = end($interests);
 7 $first = reset($interests);
 8 var_dump(key($interests));  //int 2
 9 echo "<br/>";
10 var_dump(current($interests));  //string 'music' (length=5)
11 echo "<br/>";
12 var_dump($end);     //string 'software' (length=8)
13 echo "<br/>";
14 var_dump($first);   //string 'music' (length=5)
15 ?>

Output:

D: \ wampServer \ www \ Apache Server home \ practice doing \ routine .php:. 8: 2 int 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php: 10: String 'Music' (length . 5 = ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine .php: 12 is: String 'Software' (length =. 8 ) 

D : \ WampServer \ WWW \ the Apache server main directory \ practice doing \ routine. PHP: 14: String 'Music' (length =. 5)

7. each () function

program:

 1 <?php
 2 $interests[2] = "music";
 3 $interests[5] = "movie";
 4 $interests[1] = "computer";
 5 $interests[] = "software";
 6 $each = each($interests);
 7 print_r( $each );   //Array ( [1] => music [value] => music [0] => 2 [key] => 2 )
 8 echo "<br/>";
 9 echo current($interests);   //movie
10 ?>

Output:

Description:

　　PHP 7.2 abandoned each () method.

Iterate

Use list () language structure, each () function and loops can be achieved

program:

 1 <?php
 2 $fruits = array( 'orange', 'apple', 'banana');
 3 $colors = array( 'orange', 'red', 'yellow' );
 4 $temp = array_combine( $fruits,$colors );
 5 do{
 6     $key = key($temp);
 7     $value = current($temp);
 8     echo $key." => ".$value."<br/>";
 9 }while( next($temp) );
10 ?>

输出：

orange => orange
apple => red
banana => yellow

PHP array _5_3_ array and its application handler function array pointer _3_

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