Web студия "GrandView"

Оператор + присоединяет правый массив к массиву, размещенному слева НЕ перезаписывая элементы с дублирующимися ключами.

При сравнении элементы массива считаются идентичными, если совпадает и ключ, и соответствующее значение.

Пример 15-3. Сравнение массивов


<?php

$a = array("apple", "banana");

$b = array(1 => "banana", "0" => "apple");



var_dump($a == $b); // bool(true)

var_dump($a === $b); // bool(false)

?>

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Операторы, работающие с массивами

Q1712 at online dot ms
20-Apr-2007 05:54


The example may get u into thinking that the identical operator returns true because the key of apple is a string but that is not the case, cause if a string array key is the standart representation of a integer it's gets a numeral key automaticly. 



The identical operator just requires that the keys are in the same order in both arrays:



<?php

$a = array (0 => "apple", 1 => "banana");

$b = array (1 => "banana", 0 => "apple");



var_dump($a === $b); // prints bool(false) as well



$b = array ("0" => "apple", "1" => "banana");



var_dump($a === $b); // prints bool(true)

?>

puneet singh @ value-one dot com
18-Jan-2006 10:42


hi  just see one more example of union....



<?php

$a = array(1,2,3);

$b = array(1,7,8,9,10);

$c = $a + $b; // Union of $a and $b

echo "Union of \$a and \$b: \n";

//echo $c

print_r($c);

?> 

//output

Union of $a and $b: Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 9 [4] => 10 )

kit dot lester at lycos dot co dot uk
21-Aug-2005 09:01


When comparing arrays that have (some or all) element-values that are themselves array, then in PHP5 it seems that == and === are applied recursively - that is

 * two arrays satisfy == if they have the same keys, and the values at each key satisfy == for whatever they happen to be (which might be arrays);

 * two arrays satisfy === if they have the same keys, and the values at each key satisfy === for whatever (etc.).



Which explains what happens if we compare two arrays of arrays of arrays of...



Likewise, the corresponding inversions for != <> and !==.



I've tested this to array-of-array-of-array, which seems fairly convincing. I've not tried it in PHP4 or earlier.

kit dot lester at lycos dot co dot uk
21-Aug-2005 08:44


This manual page doesn't mention < & co for arrays, but example 15-2 in 

    http://www.php.net/manual/en/language.operators.comparison.php

goes to some lengths to explain how they work.

Peter
29-Oct-2004 07:57


The code from texbungalow at web dot de below is slightly incorrect.  If my memory from primary school history is correct, roman numerals don't allow things like MIM - it has to be MCMXCIX, ie each step is only 1 level down (sorry, I can't explain it very well.



a print_r($segments) comparing the snippets should explain.



Corrected code:

<?php

function roman ($nr ) {

     $base_digits= array (

           1=> "I", 

           10=> "X", 

           100=> "C", 

           1000=> "M", 

           );

     $help_digits= array (

           5=> "V", 

           50=> "L", 

           500=> "D", 

           );

     $all_digits= $base_digits+ $help_digits;

     foreach ($base_digits as $key1=> $value1 )

           foreach ($all_digits as $key2=> $value2 )

                 if ($key1< $key2 && $key1 >= ($key2 / 10)) 

                       $segments[$key2- $key1 ]= $value1. $value2;

     $segments+= $all_digits;

     krsort ($segments );

     foreach ($segments as $key=> $value )

           while ($key<= $nr ) {

                 $nr-= $key;

                 $str.= $value;

                 }

     return $str;

     }

echo roman (1998);   //  prints MCMXCVIII

?>

dfranklin at fen dot com
22-Apr-2004 01:40


Note that + will not renumber numeric array keys.  If you have two numeric arrays, and their indices overlap, + will use the first array's values for each numeric key, adding the 2nd array's values only where the first doesn't already have a value for that index.  Example:



$a = array('red', 'orange');

$b = array('yellow', 'green', 'blue');

$both = $a + $b;

var_dump($both);



Produces the output:



array(3) { [0]=>  string(3) "red" [1]=>  string(6) "orange" [2]=>  string(4) "blue" }



To get a 5-element array, use array_merge.



    Dan

texbungalow at web dot de
26-Apr-2003 06:46


use '+=' to quickly append an array to another one:



function roman ($nr ) {

      $base_digits= array (

            1=> "I", 

            10=> "X", 

            100=> "C", 

            1000=> "M", 

            );

      $help_digits= array (

            5=> "V", 

            50=> "L", 

            500=> "D", 

            );

      $all_digits= $base_digits+ $help_digits;

      foreach ($base_digits as $key1=> $value1 )

            foreach ($all_digits as $key2=> $value2 )

                  if ($key1< $key2 ) 

                        $segments[$key2- $key1 ]= $value1. $value2;

      $segments+= $all_digits;

      krsort ($segments );

      foreach ($segments as $key=> $value )

            while ($key<= $nr ) {

                  $nr-= $key;

                  $str.= $value;

                  }

      return $str;

      }



echo roman (888);   //  prints DCCCLXXXVIII

amirlaher AT yahoo DOT co SPOT uk
09-Dec-2002 10:41


[]= could be considered an Array Operator (in the same way that .= is a String Operator). 

[]= pushes an element onto the end of an array, similar to array_push:

<? 

  $array= array(0=>"Amir",1=>"needs");

  $array[]= "job";

  print_r($array);

?>

Prints: Array ( [0] => Amir [1] => needs [2] => job )

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