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Add

Add or remove element from array 
 
/**
 * array_push()     add at the end
 * array_shift()    extract first
 * array_unshift()  add at beggining
 * arrau_pop()      extract last
 */

$A = [1, 2];
$B = [2, 3];
$C = [1, 2];
$D = [2, 4];

array_push($A, 3);
$A[] = 4; // faster
print_r($A); // 1,2,3,4

echo array_shift($B); // 2 (first)

array_unshift($C, 100);
print_r($C); // 100,1,2

echo array_pop($D); // 4

Slice

Extract a slice of the array 
 
/**
 * array_slice(), array_splice()
 * 
 * Extract or remove a portion from array
 */

$A = [1, 2, 3, 4, 5];

print_r(array_slice($A, 2)); // 3, 4, 5
print_r(array_slice($A, 0, 2)); // 1, 2
print_r(array_slice($A, -2, 1)); // [0] => 4
print_r(array_slice($A, -2, 1, true)); // [3] => 4 (preserve keys)

$B = array(1, 2, 3, 4, 5);

print_r(array_splice($B, 2)); // [ 1, 2 ]

Duplicates

array_unique() - Remove duplicate values from an array 
 
/**
 * array_unique()
 * 
 * Removes duplicate values from an array
 */

$A = [1, 2, 'b'=>'green', 2];

$B = array_unique($A);
print_r($B); // 1, 2, green

Padding

Pad array to the specified length with a value. 
 
/**
 * array_pad()
 * 
 * Pad an array to the specified length
 */

$A = [1,2,3];
$B = array_pad($A, 6, 0); 

print_r($B); // 1, 2, 3, 0, 0, 0

echo str_pad(111, 6, 0); // 111000






Questions and answers




Remove duplicates values from an array?

  • a) array_diff($array);
  • c) array_unique($array);

Reverse the order of array elements

  • a) $b = array_reverse($a);
  • b) $b = array_flip($a);

  • a) [3, 4, 5]
  • b) [1, 2]


References