minte9
LearnRemember / PHP



Keys

You can add an element to an array without specifying a key. 
 
/**
 * PHP automaticaly assign a number as key ...
 * The new key > the greatest key
 * 
 * Array keys are case-sensitive, but type insensitive
 */

$A = array(2 => 5);
$B = array('4' => 5, 'a' => 'b');
$C = ['A' => 1, 'a' => 2, '1' => 3, 1=> 4, '01' => 5];

$A[] = 'a'; // key = 3
$B[] = 44;  // key = 5

var_dump( $A[3] == 'a' ); // true
var_dump( $B[5] == 44 );  // true

var_dump( $C['A'] == $C['a'] ); // false
var_dump( $C['1'] == $C[1] );   // true

print_r($C); // A=>1, a=>2, 1=>4, 01=>5

List

List constructor assign array's values to individual variables. 
 
/**
 * list() 
 * 
 * Not really a function, but a language construct
 * List doesn't work with strings, use explode()
 * 
 * Extract assign multiple variables ...
 * from key/value array
 */

$USER = ["John", "34", "07288333"];
$date = '25/05/2012';
$DATA = ['b'=>2, 'c'=>3];

list($name, $age) = $USER;
list($day, $month, $year) = explode('/', $date);

print_r("$name is $age years old"); // John is 34 years old
print_r($month); // 05

extract($DATA);
var_dump( $b == 2); // true



  Last update: 627 days ago




Questions and answers




$x[] = 0;

  • a) Array
  • b) 11

  • a) 2
  • b) 23

  • a) 2
  • b) Notice: Undefined variable

Which function outputs value's type?

  • a) var_dump
  • b) print_r

How do you assign variables from key/value array?

  • a) extract()
  • b) list()


References





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