Смотрите также
A simple trick that can help you to guess what diff/intersect or sort function does by name.
[suffix] assoc — additional index check. Compares both value and index.Example: array_diff_assoc, array_intersect_assoc.
[suffix] key — index only check. Ignores value of array, compares only indexes.Example: array_diff_key, array_intersect_key.
[suffix] **empty** — no «key» or «assoc» word in suffix. Compares values only. Ignores indexes of array.Example: array_diff, array_intersect.
[prefix] u — will do comparison with user defined function. Letter u can be used twice in some functions (like array_udiff_uassoc), this means that you have to use 2 functions (one for value, one for index).Example: array_udiff_uassoc, array_uintersect_assoc.
This also works with array sort functions:
[prefix] a — associative. Will preserve keys. [prefix] k — key sort. Will sort array by keys. [prefix] r — reverse. Will sort array in reverse order. [prefix] u — sort by user defined function (same as for diff/intersect).Big arrays use a lot of memory possibly resulting in memory limit errors. You can reduce memory usage on your script by destroying them as soon as you´re done with them. I was able to get over a few megabytes of memory by simply destroying some variables I didn´t use anymore.
You can view the memory usage/gain by using the funcion memory_get_usage(). Hope this helps!
I need to take an element from the Array and change its position within the Array by moving the rest of the elements as required.
This is the function that does it. The first parameter is the working Array. The second is the position of the element to move and the third is the position where to move the element.
The function returns the modified Array.
function array_move_elem ( $array , $from , $to ) if ( $from == $to ) < return $array ; >
$c = count ( $array );
if (( $c > $from ) and ( $c > $to )) if ( $from < $to ) $f = $array [ $from ];
for ( $i = $from ; $i < $to ; $i ++) $array [ $i ] = $array [ $i + 1 ];
>
$array [ $to ] = $f ;
> else $f = $array [ $from ];
for ( $i = $from ; $i > $to ; $i —) $array [ $i ] = $array [ $i — 1 ];
>
$array [ $to ] = $f ;
>
?>
Examples:
$array = array( ‘Cero’ , ‘Uno’ , ‘Dos’ , ‘Tres’ , ‘Cuatro’ , ‘Cinco’ , ‘Seis’ , ‘Siete’ , ‘Ocho’ , ‘Nueve’ , ‘Diez’ );
$array = array_move_elem ( $array , 3 , 5 ); // Move element in position 3 to position 5.
print_r ( $array );
$array = array_move_elem ( $array , 5 , 3 ); // Move element in position 5 to position 3, leaving array as it was. 😉
print_r ( $array );
?>
Return:
Array ( [ 0 ] => Cero [ 1 ] => Uno [ 2 ] => Dos [ 3 ] => Cuatro [ 4 ] => Cinco [ 5 ] => Tres [ 6 ] => Seis [ 7 ] => Siete [ 8 ] => Ocho [ 9 ] => Nueve [ 10 ] => Diez )
Array ( [ 0 ] => Cero [ 1 ] => Uno [ 2 ] => Dos [ 3 ] => Tres [ 4 ] => Cuatro [ 5 ] => Cinco [ 6 ] => Seis [ 7 ] => Siete [ 8 ] => Ocho [ 9 ] => Nueve [ 10 ] => Diez )
?>
Updated code of ‘indioeuropeo’ with option to input string-based keys.
FUNCTION:
function array_move_elem ( $array , $from , $to ) // return if non-numeric couldn’t be found or from=to
if(! is_numeric ( $from )) if( array_search ( $from , array_keys ( $array ))!== FALSE ) $from = array_search ( $from , array_keys ( $array ));
>else return $array ;
>
>
$array_numeric_keys = array();
foreach( $array as $k => $v ) $array_numeric_keys [] = $k ;
>
if ( $from == $to ) < return $array ; >
$c = count ( $array_numeric_keys );
if (( $c > $from ) and ( $c > $to )) if ( $from < $to ) $f = $array_numeric_keys [ $from ];
for ( $i = $from ; $i < $to ; $i ++) $array_numeric_keys [ $i ] = $array_numeric_keys [ $i + 1 ];
>
$array_numeric_keys [ $to ] = $f ;
> else $f = $array_numeric_keys [ $from ];
for ( $i = $from ; $i > $to ; $i —) $array_numeric_keys [ $i ] = $array_numeric_keys [ $i — 1 ];
>
$array_numeric_keys [ $to ] = $f ;
>
>
$array_new = array();
foreach( $array_numeric_keys as $v ) $array_new [ $v ] = $array [ $v ];
>
return $array_new ;
>
?>
Here is a function to find out the maximum depth of a multidimensional array.
// return depth of given array
// if Array is a string ArrayDepth() will return 0
// usage: int ArrayDepth(array Array)
function ArrayDepth ( $Array , $DepthCount =- 1 , $DepthArray =array()) $DepthCount ++;
if ( is_array ( $Array ))
foreach ( $Array as $Key => $Value )
$DepthArray []= ArrayDepth ( $Value , $DepthCount );
else
return $DepthCount ;
foreach( $DepthArray as $Value )
$Depth = $Value > $Depth ? $Value : $Depth ;
return $Depth ;
>
?>
While PHP has well over three-score array functions, array_rotate is strangely missing as of PHP 5.3. Searching online offered several solutions, but the ones I found have defects such as inefficiently looping through the array or ignoring keys.
The following array_rotate() function uses array_merge and array_shift to reliably rotate an array forwards or backwards, preserving keys. If you know you can trust your $array to be an array and $shift to be between 0 and the length of your array, you can skip the function definition and use just the return expression in your code.
function array_rotate ( $array , $shift ) if(! is_array ( $array ) || ! is_numeric ( $shift )) if(! is_array ( $array )) error_log ( __FUNCTION__ . ‘ expects first argument to be array; ‘ . gettype ( $array ). ‘ received.’ );
if(! is_numeric ( $shift )) error_log ( __FUNCTION__ . ‘ expects second argument to be numeric; ‘ . gettype ( $shift ). » ` $shift ` received.» );
return $array ;
>
$shift %= count ( $array ); //we won’t try to shift more than one array length
if( $shift < 0 ) $shift += count ( $array ); //handle negative shifts as positive
return array_merge ( array_slice ( $array , $shift , NULL , true ), array_slice ( $array , 0 , $shift , true ));
>
?>
A few simple tests:
$array =array( «foo» => 1 , «bar» => 2 , «baz» => 3 , 4 , 5 );
print_r ( array_rotate ( $array , 2 ));
print_r ( array_rotate ( $array , — 2 ));
print_r ( array_rotate ( $array , count ( $array )));
print_r ( array_rotate ( $array , «4» ));
print_r ( array_rotate ( $array , — 9 ));
?>
Short function for making a recursive array copy while cloning objects on the way.
function arrayCopy ( array $array ) $result = array();
foreach( $array as $key => $val ) if( is_array ( $val ) ) $result [ $key ] = arrayCopy ( $val );
> elseif ( is_object ( $val ) ) $result [ $key ] = clone $val ;
> else $result [ $key ] = $val ;
>
>
return $result ;
>
?>
/*to change an index without rewriting the whole table and leave at the same place.
*/
function change_index (& $tableau , $old_key , $new_key ) $changed = FALSE ;
$temp = 0 ;
foreach ( $tableau as $key => $value ) switch ( $changed ) case FALSE :
//creates the new key and deletes the old
if ( $key == $old_key ) $tableau [ $new_key ] = $tableau [ $old_key ];
unset( $tableau [ $old_key ]);
$changed = TRUE ;
>
break;
case TRUE :
//moves following keys
if ( $key != $new_key ) $temp = $tableau [ $key ];
unset( $tableau [ $key ]);
$tableau [ $key ] = $temp ;
break;
>
else < $changed = FALSE ;>//stop
>
>
array_values ( $tableau ); //free_memory
>
//Result :
$tableau = array( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 );
$res = print_r ( $tableau , TRUE );
$longueur = strlen ( $res ) — 1 ;
echo «Old array :\n» . substr ( $res , 8 , $longueur ) . «\n» ;
change_index ( $tableau , 2 , ‘number 2’ );
$res = print_r ( $tableau , TRUE );
$longueur = strlen ( $res ) — 10 ;
echo «New array :\n» . substr ( $res , 8 , $longueur ) . «\n» ;
krsort
Замечание:
Если оба сравниваемых значения эквивалентны, они сохраняют свой первоначальный порядок. До PHP 8.0.0 их относительный порядок в отсортированном массиве не был определён.
Замечание:
Сбрасывает внутренний указатель массива на первый элемент.
Список параметров
Необязательный второй параметр flags может использоваться для изменения поведения сортировки с использованием следующих значений:
- SORT_REGULAR — обычное сравнение элементов; подробности описаны в разделе операторы сравнения
- SORT_NUMERIC — числовое сравнение элементов
- SORT_STRING — строковое сравнение элементов
- SORT_LOCALE_STRING — сравнение элементов как строки на основе текущего языкового стандарта. Используется языковой стандарт, который можно изменить с помощью setlocale()
- SORT_NATURAL — сравнение элементов как строки, используя «естественный порядок», например natsort()
- SORT_FLAG_CASE — можно объединять (побитовое ИЛИ) с SORT_STRING или SORT_NATURAL для сортировки строк без учёта регистра
Возвращаемые значения
Функция всегда возвращает true .
Список изменений
| Версия | Описание |
|---|---|
| 8.2.0 | Тип возвращаемого значения теперь true ; ранее было bool . |
Примеры
Пример #1 Пример использования krsort()
$fruits = array( «d» => «lemon» , «a» => «orange» , «b» => «banana» , «c» => «apple» );
krsort ( $fruits );
foreach ( $fruits as $key => $val ) echo » $key = $val \n» ;
>
?>
Результат выполнения данного примера:
d = lemon c = apple b = banana a = orange
Смотрите также
- sort() — Сортирует массив по возрастанию
- ksort() — Сортирует массив по ключу в порядке возрастания
- Сравнение функций сортировки массивов
User Contributed Notes 2 notes
To create a natural reverse sorting by keys, use the following function:
function natkrsort ( $array )
$keys = array_keys ( $array );
natsort ( $keys );
foreach ( $keys as $k )
$new_array [ $k ] = $array [ $k ];
>
$new_array = array_reverse ( $new_array , true );
This is a function that will sort an array with integer keys (weight) and float values (cost) and delete ‘bad deals’ — entries that are more costly than other entries that have greater or equal weight.
Input: an array of unsorted weight/cost pairs
Output: none
function BEST_DEALS($myarray)
< // most weight for least cost:
// ? Peter Kionga-Kamau, http://www.pmkmedia.com
// thanks to Nafeh for the reversal trick
// free for unrestricted use.
krsort($myarray, SORT_NUMERIC);
while(list($weight, $cost) = each($myarray))
< // delete bad deals, retain best deals:
if(!$lastweight)
$lastweight=$weight;
$lastcost = $cost;
>
else if($cost >= $lastcost) unset($myarray[$weight]);
else
$lastweight=$weight;
$lastcost = $cost;
>
>
ksort($myarray);
>
- Функции для работы с массивами
- array_change_key_case
- array_chunk
- array_column
- array_combine
- array_count_values
- array_diff_assoc
- array_diff_key
- array_diff_uassoc
- array_diff_ukey
- array_diff
- array_fill_keys
- array_fill
- array_filter
- array_flip
- array_intersect_assoc
- array_intersect_key
- array_intersect_uassoc
- array_intersect_ukey
- array_intersect
- array_is_list
- array_key_exists
- array_key_first
- array_key_last
- array_keys
- array_map
- array_merge_recursive
- array_merge
- array_multisort
- array_pad
- array_pop
- array_product
- array_push
- array_rand
- array_reduce
- array_replace_recursive
- array_replace
- array_reverse
- array_search
- array_shift
- array_slice
- array_splice
- array_sum
- array_udiff_assoc
- array_udiff_uassoc
- array_udiff
- array_uintersect_assoc
- array_uintersect_uassoc
- array_uintersect
- array_unique
- array_unshift
- array_values
- array_walk_recursive
- array_walk
- array
- arsort
- asort
- compact
- count
- current
- end
- extract
- in_array
- key_exists
- key
- krsort
- ksort
- list
- natcasesort
- natsort
- next
- pos
- prev
- range
- reset
- rsort
- shuffle
- sizeof
- sort
- uasort
- uksort
- usort
- each