array_fill()

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

用给定的值填充数组

说明

array_fill(int $start_index,int $num,mixed $value): array

array_fill()用$value参数的值将一个数组填充$num个条目，键名由$start_index参数指定的开始。

参数

$start_index

返回的数组的第一个索引值。

如果$start_index是负数，那么返回的数组的第一个索引将会是$start_index，而后面索引则从0开始。(参见例子)。

$num

插入元素的数量。必须大于或等于 0。

$value

用来填充的值。

返回值

返回填充后的数组。

错误／异常

如果$num小于零，将会抛出E_WARNING。

更新日志

范例

Example #1array_fill()例子

<?php
$a = array_fill(5, 6, 'banana');
$b = array_fill(-2, 4, 'pear');
print_r($a);
print_r($b);
?>

以上例程会输出：

Array
(
    [5]  => banana
    [6]  => banana
    [7]  => banana
    [8]  => banana
    [9]  => banana
    [10] => banana
)
Array
(
    [-2] => pear
    [0] => pear
    [1] => pear
    [2] => pear
)

注释

参见手册上数组一节里关于负数的键的详细解释。

参见

• array_fill_keys() 使用指定的键和值填充数组
• str_repeat() 重复一个字符串
• range() 根据范围创建数组，包含指定的元素

This is what I recently did to quickly create a two dimensional array (10x10), initialized to 0:
<?php
 $a = array_fill(0, 10, array_fill(0, 10, 0));
?>
This should work for as many dimensions as you want, each time passing to array_fill() (as the 3rd argument) another array_fill() function.

If you need negative indices:
<?php
$b = array_fill(-2, 4, 'pear');//this is not what we want
$c = array_fill_keys(range(-2,1),'pear');//these are negative indices
print_r($b);
print_r($c);
?>
Here is result of the code above:
Array
(
  [-2] => pear
  [0] => pear
  [1] => pear
  [2] => pear
)
Array
(
  [-2] => pear
  [-1] => pear
  [0] => pear
  [1] => pear
)

Using objects with array_fill may cause unexpected results. Consider the following:
<?php
class Foo {
  public $bar = "banana";
}
//fill an array with objects
$array = array_fill(0, 2, new Foo());
var_dump($array);
/*
array(2) {
 [0]=>
 object(Foo)#1 (1) {
  ["bar"]=>
  string(6) "banana"
 }
 [1]=>
 object(Foo)#1 (1) {
  ["bar"]=>
  string(6) "banana"
 }
} */
//now we change the attribute of the object stored in index 0
//this actually changes the attribute for EACH object in the ENTIRE array
$array[0]->bar = "apple";
var_dump($array);
/*
array(2) {
 [0]=>
 object(Foo)#1 (1) {
  ["bar"]=>
  string(5) "apple"
 }
 [1]=>
 object(Foo)#1 (1) {
  ["bar"]=>
  string(5) "apple"
 }
}
 */
?>
Objects are filled in the array BY REFERENCE. They are not copied for each element in the array.

I made this function named "array_getMax" that returns te maximum value and index, from array:
<?php
//using array_search_all by helenadeus at gmail dot com
function array_search_all($needle, $haystack)
{#array_search_match($needle, $haystack) returns all the keys of the values that match $needle in $haystack
  foreach ($haystack as $k=>$v) {
  
    if($haystack[$k]==$needle){
    
      $array[] = $k;
    }
  }
  return ($array);
  
}
function array_getMax($array){
    
  $conteo=array_count_values($array);
  
  if( count($conteo)==1 ){//returns full array when all values are the same.
    return $array;    
  }
    
  arsort($array);
  
  //$antValue=null;
  $maxValue=null;
  $keyValue=null;
  foreach($array as $key=>$value){
    if($maxValue==null){
      $maxValue=$value;
      $keyValue=$key;
      break;
    }    
  }
  
  $resultSearch=array_search_all($maxValue, $array);
    
  return array_fill_keys($resultSearch, $maxValue);
  
  
}
//example 
 $arreglo=array('e1'=>99,'e2'=>'99','e3'=>1,'e4'=>1,'e5'=>98);
  
  var_dump(array_getMax($arreglo));
//output
/*
array(2) {
 ["e1"]=>
 int(99)
 ["e2"]=>
 int(99)
}
*/
?>
I hope some one find this usefull

Fill missing keys in a (numerically-indexed) array with a default value
<?php
function fill_missing_keys($array, $default = null, $atleast = 0)
{
  return $array + array_fill(0, max($atleast, max(array_keys($array))), $default);
}
?>

array_fill() cannot be used to setup only missing keys in an array. This may be necessary for example before using implode() on a sparse filled array.
The solution is to use this function:
<?php
function array_setkeys(&$array, $fill = NULL) {
 $indexmax = -1;
 for (end($array); $key = key($array); prev($array)) {
  if ($key > $indexmax)
   $indexmax = $key;
 }
 for ($i = 0; $i <= $indexmax; $i++) {
  if (!isset($array[$i]))
   $array[$i] = $fill;
 }
 ksort($array);
}
?>
This is usefull in some situations where you don't know which key index was filled and you want to preserve the association between a positioned field in an imploded array and the key index when exploding it.