Arrays Flashcards
1
Q
How do you create a new array?
A
$array = array(); or $array[0] = “info” or range() for numeric arrays.
2
Q
What are the types of arrays?
A
Indexed arrays - Arrays with a numeric index
Associative arrays - Arrays with named keys
Multidimensional arrays - Arrays containing one or more arrays
3
Q
How do you access data from an associative array?
A
$array[‘string’]
4
Q
How do you access data from a numeric array?
A
$array[N] where N = a positive integer
5
Q
How do you add to the end of an array?
A
$array[] = value;
6
Q
Can you add keys to an array out of order?
A
Yes, keys can be added in any order.
7
Q
How do you initialize a multidimensional array?
A
array(array(), array(), etc.)
8
Q
How do you make a single assignment in a multi-dimensional array?
A
$array[][] = value
9
Q
How do you access a single cell in a multidimensional array?
A
$array[key][key];
10
Q
How do you search an array by value?
A
in_array() and array_search()
11
Q
How do you search an array by key?
A
array_key_exists() or isset($array[“key”])
12
Q
What is the difference between array_key_exists() and isset()?
A
array_key_exists will tell you if a key exists in an array, whereas isset will only return true if the key/variable exists and is not null.
13
Q
How do you find the length of an array?
A
count($array)
14
Q
What is the difference between sort() and asort()?
A
sort() is used for numeric arrays and will reset keys in an associative array to numbers, whereas asort() can be used to sort and associative array and maintain the current keys.
15
Q
How do you sort a multidimensional array?
A
array_multisort(array1,sorting order,sorting type,array2,array3…)
EXAMPLE:
$a=array(“Dog”,”Cat”,”Horse”,”Bear”,”Zebra”);
array_multisort($a);
print_r($a);
OUTPUT:
Array ( [0] => Bear [1] => Cat [2] => Dog [3] => Horse [4] => Zebra )
16
Q
How would you sort this array and its children into descending order?
$matrix = array(array(1, 2, 3), array(4, 5, 6), array(7, 8, 9));
A
array_multisort($matrix, SORT_DESC);
array_multisort($matrix[0], SORT_DESC, $matrix[1], SORT_DESC, $matrix[2], SORT_DESC);
17
Q
How do you remove an array element from the end?
A
array_pop(array)
EXAMPLE:
$a=array(“red”,”green”,”blue”);
array_pop($a);
print_r($a);
Array ( [0] => red [1] => green )
18
Q
How would you measure the difference between these 2 arrays?
$array1 = array(1, 2, 3, 4, 5, 6, 7); $array2 = array(2, 4, 6, 8);
A
array_diff($array1, $array2)
19
Q
How would you copy and create a new array from the numbers 3-7 in the following array?
$array1 = array(1, 2, 3, 4, 5, 6, 7, 8, 9);
A
$array2 = array_slice($array1, 2, 5);
20
Q
How would you merge these two array?
$array1 = array('a' => 'Apples', 'b' => 'Oranges', 'c' => 'Bananas', 'd' => 'Grapes');
$array2 = array('d' => 'Kiwi', 'e' => 'Plums', 'f' => 'Pears', 'g' => 'Cherries');
A
$array3 = array_merge($array1, $array2);
21
Q
What will be the result?
$array1 = array('a' => 'Apples', 'b' => 'Oranges', 'c' => 'Bananas', 'd' => 'Grapes');
$array2 = array('d' => 'Kiwi', 'e' => 'Plums', 'f' => 'Pears', 'g' => 'Cherries');
$array3 = array_merge($array1, $array2);
A
array(7) { [“a”]=> “Apples” [“b”]=> “Oranges” [“c”]=> “Bananas” [“d”]=> “Kiwi” [“e”]=> “Plums” [“f”]=> “Pears” [“g”]=> “Cherries” }
22
Q
How do you change all keys in an array to lowercase or uppercase?
A
array_change_key_case(array,case);
CASE_LOWER - Default value. Changes the keys to lowercase
CASE_UPPER - Changes the keys to uppercase
EXAMPLE:
$age=array(“Peter”=>”35”,”Ben”=>”37”,”Joe”=>”43”);
print_r(array_change_key_case($age,CASE_UPPER));
OUTPUT:
Array ( [PETER] => 35 [BEN] => 37 [JOE] => 43 )
23
Q
How do you split an array into chunks of arrays?
A
array_chunk(array,size,preserve_key);
EXAMPLE:
$cars=array(“Volvo”,”BMW”,”Toyota”,”Honda”,”Mercedes”,”Opel”);
print_r(array_chunk($cars,2));
OUTPUT:
Array ( [0] => Array ( [0] => Volvo [1] => BMW ) [1] => Array ( [0] => Toyota [1] => Honda ) [2] => Array ( [0] => Mercedes [1] => Opel ) )
24
Q
How do you return the values from a single column in the input array?
A
array_column(array,column_key,index_key);
EXAMPLE:
$a = array(
array(
'id' => 5698,
'first_name' => 'Peter',
'last_name' => 'Griffin',
),
array(
'id' => 4767,
'first_name' => 'Ben',
'last_name' => 'Smith',
),
array(
'id' => 3809,
'first_name' => 'Joe',
'last_name' => 'Doe',
)
);
$last_names = array_column($a, ‘last_name’);
print_r($last_names);
OUTPUT:
Array ( [0] => Griffin [1] => Smith [2] => Doe )
25
How do you create an array by using the elements from one "keys" array and one "values" array?
array_combine(keys,values);
-----------------------
EXAMPLE:
$fname=array("Peter","Ben","Joe");
$age=array("35","37","43");
$c=array_combine($fname,$age);
print_r($c);
OUTPUT:
Array ( [Peter] => 35 [Ben] => 37 [Joe] => 43 )
26
How do you count all the values of an array?
array_count_values(array);
-----------------------
EXAMPLE:
$a=array("A","Cat","Dog","A","Dog");
print_r(array_count_values($a));
OUTPUT:
Array ( [A] => 2 [Cat] => 1 [Dog] => 2 )
27
How do you compare the VALUES of two (or more) arrays, and return the differences?
array_diff(array1,array2,array3...);
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("e"=>"red","f"=>"black","g"=>"purple");
$a3=array("a"=>"red","b"=>"black","h"=>"yellow");
$result=array_diff($a1,$a2,$a3);
print_r($result);
OUTPUT:
Array ( [b] => green [c] => blue )
28
How do you compare the keys AND values of two (or more) arrays, and return the differences?
array_diff_assoc(array1,array2,array3...);
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("a"=>"red","b"=>"green","c"=>"blue");
$result=array_diff_assoc($a1,$a2);
print_r($result);
OUTPUT:
Array ( [d] => yellow )
29
How do you compare the KEYS of two (or more) arrays, and return the differences?
array_diff_key(array1,array2,array3...);
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("c"=>"yellow","d"=>"black","e"=>"brown");
$a3=array("f"=>"green","c"=>"purple","g"=>"red");
$result=array_diff_key($a1,$a2,$a3);
print_r($result);
OUTPUT:
Array ( [a] => red [b] => green )
30
How can you compare arrays, and return the differences (compare keys AND values, using a user-defined key comparison function)?
array_diff_uassoc(array1,array2,array3...,myfunction);
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"green","d"=>"blue");
$a3=array("e"=>"yellow","a"=>"red","d"=>"blue");
$result=array_diff_uassoc($a1,$a2,$a3,"myfunction");
print_r($result);
OUTPUT:
Array ( [c] => blue )
31
How do you compare arrays, and return the differences (compare KEYS only, using a user-defined key comparison function)?
array_diff_ukey(array1,array2,array3...,myfunction);
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"black","b"=>"yellow","d"=>"brown");
$a3=array("e"=>"purple","f"=>"white","a"=>"gold");
$result=array_diff_ukey($a1,$a2,$a3,"myfunction");
print_r($result);
OUTPUT:
Array ( [c] => blue )
32
How do you fill an array with values?
array_fill(index,number,value);
-----------------------
EXAMPLE:
```
$a1=array_fill(3,4,"blue");
$b1=array_fill(0,1,"red");
print_r($a1);
echo "
"; print_r($b1); ``` OUTPUT: Array ( [3] => blue [4] => blue [5] => blue [6] => blue ) Array ( [0] => red )
"; print_r($b1); ``` OUTPUT: Array ( [3] => blue [4] => blue [5] => blue [6] => blue ) Array ( [0] => red )
33
How do you fill an array with values, specifying keys?
array_fill_keys(keys,value);
-----------------------
EXAMPLE:
$keys=array("a","b","c","d");
$a1=array_fill_keys($keys,"blue");
print_r($a1);
OUTPUT:
Array ( [a] => blue [b] => blue [c] => blue [d] => blue )
34
How do you filter the values of an array using a callback function?
array_filter(array,callbackfunction);
-----------------------
EXAMPLE:
```
function test_odd($var)
{
return($var & 1);
}
```
$a1=array("a","b",2,3,4);
print_r(array_filter($a1,"test_odd"));
OUTPUT:
Array ( [3] => 3 )
35
How do you flip/exchange all keys with their associated values in an array?
array_flip(array);
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$result=array_flip($a1);
print_r($result);
OUTPUT:
Array ( [red] => a [green] => b [blue] => c [yellow] => d )
36
How do you compare arrays, and returns the matches (compare values only)?
array_intersect(array1,array2,array3...);
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("e"=>"red","f"=>"green","g"=>"blue");
$result=array_intersect($a1,$a2);
print_r($result);
OUPUT:
Array ( [a] => red [b] => green [c] => blue )
37
How do you compare arrays and returns the matches (compare keys and values)?
array_intersect_assoc(array1,array2,array3...)
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("a"=>"red","b"=>"green","c"=>"blue");
$result=array_intersect_assoc($a1,$a2);
print_r($result);
OUTPUT:
Array ( [a] => red [b] => green [c] => blue )
38
How do you compare arrays, and return the matches (compare keys only)?
array_intersect_key(array1,array2,array3...)
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","c"=>"blue","d"=>"pink");
$result=array_intersect_key($a1,$a2);
print_r($result);
OUTPUT:
Array ( [a] => red [c] => blue )
39
How do you compare arrays, and return the matches (compare keys and values, using a user-defined key comparison function)?
array_intersect_uassoc(array1,array2,array3...,myfunction)
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("d"=>"red","b"=>"green","e"=>"blue");
$result=array_intersect_uassoc($a1,$a2,"myfunction");
print_r($result);
OUTPUT:
Array ( [b] => green )
40
How do you compare arrays, and return the matches (compare keys only, using a user-defined key comparison function)
array_intersect_ukey(array1,array2,array3...,myfunction)
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"blue","b"=>"black","e"=>"blue");
$result=array_intersect_ukey($a1,$a2,"myfunction");
print_r($result);
OUTPUT:
Array ( [a] => red [b] => green )
41
How do you check if the specified key exists in the array?
array_key_exists(key,array)
-----------------------
EXAMPLE:
```
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (array_key_exists("Volvo",$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
```
OUTPUT:
Key exists!
42
How do you return all the keys of an array?
array_keys(array,value,strict)
-----------------------
EXAMPLE:
$a=array("Volvo"=>"XC90","BMW"=>"X5","Toyota"=>"Highlander");
print_r(array_keys($a));
OUTPUT:
Array ( [0] => Volvo [1] => BMW [2] => Toyota )
43
How do you send each value of an array to a user-made function, which returns new values?
array_map(myfunction,array1,array2,array3...)
-----------------------
EXAMPLE:
```
function myfunction($num)
{
return($num*$num);
}
```
$a=array(1,2,3,4,5);
print_r(array_map("myfunction",$a));
OUTPUT:
Array ( [0] => 1 [1] => 4 [2] => 9 [3] => 16 [4] => 25 )
44
How do you merge one or more arrays into one array?
array_merge(array1,array2,array3...)
-----------------------
EXAMPLE:
$a1=array("red","green");
$a2=array("blue","yellow");
print_r(array_merge($a1,$a2));
OUTPUT:
Array ( [0] => red [1] => green [2] => blue [3] => yellow )
45
How do you merge one or more arrays into one array recursively
array_merge_recursive(array1,array2,array3...)
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green");
$a2=array("c"=>"blue","b"=>"yellow");
print_r(array_merge_recursive($a1,$a2));
OUTPUT:
Array ( [a] => red [b] => Array ( [0] => green [1] => yellow ) [c] => blue )
46
How do you insert a specified number of items, with a specified value, to an array?
array_pad(array,size,value)
-----------------------
EXAMPLE:
$a=array("red","green");
print_r(array_pad($a,5,"blue"));
OUTPUT:
Array ( [0] => red [1] => green [2] => blue [3] => blue [4] => blue )
47
How do you calculate the product of the values in an array?
array_product(array)
-----------------------
EXAMPLE:
$a=array(5,5);
echo(array_product($a));
OUTPUT:
25
48
How do you insert one or more elements to the end of an array?
array_push(array,value1,value2...)
-----------------------
EXAMPLE:
$a=array("red","green");
array_push($a,"blue","yellow");
print_r($a);
OUTPUT:
Array ( [0] => red [1] => green [2] => blue [3] => yellow )
49
How do you return one or more random keys from an array?
array_rand(array,number)
-----------------------
EXAMPLE:
```
$a=array("red","green","blue","yellow","brown");
$random_keys=array_rand($a,3);
echo $a[$random_keys[0]]."
"; echo $a[$random_keys[1]]."
"; echo $a[$random_keys[2]]; ``` OUTPUT: green yellow brown
"; echo $a[$random_keys[1]]."
"; echo $a[$random_keys[2]]; ``` OUTPUT: green yellow brown
50
How do you return an array as a string, using a user-defined function?
array_reduce(array,myfunction,initial)
-----------------------
EXAMPLE:
```
function myfunction($v1,$v2)
{
return $v1 . "-" . $v2;
}
$a=array("Dog","Cat","Horse");
print_r(array_reduce($a,"myfunction"));
```
OUTPUT:
-Dog-Cat-Horse
51
How do you replace the values of the first array with the values from following arrays?
array_replace(array1,array2,array3...)
-----------------------
EXAMPLE:
$a1=array("red","green");
$a2=array("blue","yellow");
print_r(array_replace($a1,$a2));
OUTPUT:
Array ( [0] => blue [1] => yellow )
52
How do you replace the values of the first array with the values from following arrays recursively?
array_replace_recursive(array1,array2,array3...)
-----------------------
EXAMPLE:
$a1=array("a"=>array("red"),"b"=>array("green","blue"));
$a2=array("a"=>array("yellow"),"b"=>array("black"));
$a3=array("a"=>array("orange"),"b"=>array("burgundy"));
print_r(array_replace_recursive($a1,$a2,$a3));
OUTPUT:
Array ( [a] => Array ( [0] => orange ) [b] => Array ( [0] => burgundy [1] => blue ) )
53
How do you return an array in the reverse order?
ray_reverse(array,preserve)
-----------------------
EXAMPLE:
$a=array("a"=>"Volvo","b"=>"BMW","c"=>"Toyota");
print_r(array_reverse($a));
OUTPUT:
Array ( [c] => Toyota [b] => BMW [a] => Volvo )
54
How do you search an array for a given value and return the key?
array_search(value,array,strict)
-----------------------
EXAMPLE:
```
$a=array("a"=>"red","b"=>"green","c"=>"blue");
echo array_search("red",$a);
```
OUTPUT:
a
55
How do you remove the first element from an array, and return the value of the removed element?
array_shift(array)
-----------------------
EXAMPLE:
```
$a=array("a"=>"red","b"=>"green","c"=>"blue");
echo array_shift($a)."
"; print_r ($a); ``` OUPUT: red Array ( [b] => green [c] => blue )
"; print_r ($a); ``` OUPUT: red Array ( [b] => green [c] => blue )
56
How do you return selected parts of an array?
array_slice(array,start,length,preserve)
-----------------------
EXAMPLE:
$a=array("red","green","blue","yellow","brown");
print_r(array_slice($a,2));
OUTPUT:
Array ( [0] => blue [1] => yellow [2] => brown )
57
How do you remove AND replace specified elements of an array?
array_splice(array,start,length,array)
-----------------------
EXAMPLE:
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("a"=>"purple","b"=>"orange");
array_splice($a1,0,2,$a2);
print_r($a1);
OUTPUT:
Array ( [0] => purple [1] => orange [c] => blue [d] => yellow )
58
How do you return the sum of the values in an array?
array_sum(array)
-----------------------
EXAMPLE:
```
$a=array(5,15,25);
echo array_sum($a);
```
OUTPUT:
45
59
How do you compare arrays, and return the differences (compare values only, using a user-defined key comparison function)?
array_udiff(array1,array2,array3...,myfunction)
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"blue","b"=>"black","e"=>"blue");
$result=array_udiff($a1,$a2,"myfunction");
print_r($result);
OUTPUT:
Array ( [a] => red [b] => green )
60
How do you compare arrays, and return the differences (compare keys and values, using a built-in function to compare the keys and a user-defined function to compare the values)?
array_udiff_assoc(array1,array2,array3...,myfunction)
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"blue","c"=>"green");
$result=array_udiff_assoc($a1,$a2,"myfunction");
print_r($result);
OUTPUT:
Array ( [b] => green [c] => blue )
61
How do you compare arrays, and return the differences (compare keys and values, using two user-defined key comparison functions)
array_udiff_uassoc(array1,array2,array3...,myfunction_key,myfunction_value)
-----------------------
EXAMPLE:
```
function myfunction_key($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
```
function myfunction_value($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"green","c"=>"green");
$result=array_udiff_uassoc($a1,$a2,"myfunction_key","myfunction_value");
print_r($result);
OUTPUT:
Array ( [c] => blue )
62
How do you compare arrays, and return the matches (compare values only, using a user-defined key comparison function)
array_uintersect(array1,array2,array3...,myfunction)
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"blue","b"=>"black","e"=>"blue");
$result=array_uintersect($a1,$a2,"myfunction");
print_r($result);
OUTPUT:
Array ( [c] => blue )
63
How do you compare arrays, and return the matches (compare keys and values, using a built-in function to compare the keys and a user-defined function to compare the values)?
array_uintersect_assoc(array1,array2,array3...,myfunction)
-----------------------
EXAMPLE:
```
function myfunction($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"blue","c"=>"green");
$result=array_uintersect_assoc($a1,$a2,"myfunction");
print_r($result);
OUTPUT:
Array ( [a] => red )
64
How do you compare arrays, and return the matches (compare keys and values, using two user-defined key comparison functions)?
array_uintersect_uassoc(array1,array2,array3...,myfunction_key,myfunction_value)
-----------------------
EXAMPLE:
```
function myfunction_key($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
```
function myfunction_value($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}
```
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"green","c"=>"green");
$result=array_uintersect_uassoc($a1,$a2,"myfunction_key","myfunction_value");
print_r($result);
OUTPUT:
Array ( [a] => red [b] => green )
65
Removes duplicate values from an array
array_unique(array)
-----------------------
EXAMPLE:
$a=array("a"=>"red","b"=>"green","c"=>"red");
print_r(array_unique($a));
OUPUT:
Array ( [a] => red [b] => green )
66
Adds one or more elements to the beginning of an array
array_unshift(array,value1,value2,value3...)
-----------------------
EXAMPLE:
$a=array("a"=>"red","b"=>"green");
array_unshift($a,"blue");
print_r($a);
OUPUT:
Array ( [0] => blue [a] => red [b] => green )
67
Returns all the values of an array
array_values(array)
-----------------------
EXAMPLE:
$a=array("Name"=>"Peter","Age"=>"41","Country"=>"USA");
print_r(array_values($a));
OUPUT:
Array ( [0] => Peter [1] => 41 [2] => USA )
68
Applies a user function to every member of an array
array_walk(array,myfunction,parameter...)
-----------------------
EXAMPLE:
```
function myfunction($value,$key)
{
echo "The key $key has the value $value
"; } $a=array("a"=>"red","b"=>"green","c"=>"blue"); array_walk($a,"myfunction"); ``` OUPUT: The key a has the value red The key b has the value green The key c has the value blue
"; } $a=array("a"=>"red","b"=>"green","c"=>"blue"); array_walk($a,"myfunction"); ``` OUPUT: The key a has the value red The key b has the value green The key c has the value blue
69
Applies a user function recursively to every member of an array
array_walk_recursive(array,myfunction,parameter...)
-----------------------
EXAMPLE:
```
function myfunction($value,$key)
{
echo "The key $key has the value $value
"; } $a1=array("a"=>"red","b"=>"green"); $a2=array($a1,"1"=>"blue","2"=>"yellow"); array_walk_recursive($a2,"myfunction"); ``` OUPUT: The key a has the value red The key b has the value green The key 1 has the value blue The key 2 has the value yellow
"; } $a1=array("a"=>"red","b"=>"green"); $a2=array($a1,"1"=>"blue","2"=>"yellow"); array_walk_recursive($a2,"myfunction"); ``` OUPUT: The key a has the value red The key b has the value green The key 1 has the value blue The key 2 has the value yellow
70
Sorts an associative array in descending order, according to the value
arsort(array,sortingtype);
-----------------------
EXAMPLE:
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
arsort($age);
```
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "
"; } ``` OUPUT: Key=Joe, Value=43 Key=Ben, Value=37 Key=Peter, Value=35
"; } ``` OUPUT: Key=Joe, Value=43 Key=Ben, Value=37 Key=Peter, Value=35
71
Sorts an associative array in ascending order, according to the value
asort(array,sortingtype);
-----------------------
EXAMPLE:
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
asort($age);
```
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "
"; } ``` OUPUT: Key=Peter, Value=35 Key=Ben, Value=37 Key=Joe, Value=43
"; } ``` OUPUT: Key=Peter, Value=35 Key=Ben, Value=37 Key=Joe, Value=43
72
Create array containing variables and their values
compact(var1,var2...)
-----------------------
EXAMPLE:
```
$firstname = "Peter";
$lastname = "Griffin";
$age = "41";
```
$result = compact("firstname", "lastname", "age");
print_r($result);
OUPUT:
Array ( [firstname] => Peter [lastname] => Griffin [age] => 41 )
73
Returns the number of elements in an array
count(array,mode);
-----------------------
EXAMPLE:
```
$cars=array("Volvo","BMW","Toyota");
echo count($cars);
```
OUPUT:
3
74
Returns the current element in an array
current(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
echo current($people) . "
"; OUPUT: Peter
"; OUPUT: Peter
75
Returns the current key and value pair from an array
each(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
print_r (each($people));
OUPUT:
Array ( [1] => Peter [value] => Peter [0] => 0 [key] => 0 )
76
Sets the internal pointer of an array to its last element
end(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
```
echo current($people) . "
"; echo end($people); ``` OUPUT: Peter Cleveland
"; echo end($people); ``` OUPUT: Peter Cleveland
77
Imports variables into the current symbol table from an array
extract(array,extract_rules,prefix)
-----------------------
EXAMPLE:
$a = "Original";
$my_array = array("a" => "Cat","b" => "Dog", "c" => "Horse");
extract($my_array);
echo "\$a = $a; \$b = $b; \$c = $c";
OUPUT:
$a = Cat; $b = Dog; $c = Horse
78
Checks if a specified value exists in an array
in_array(search,array,type)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
```
if (in_array("Glenn", $people))
{
echo "Match found";
}
else
{
echo "Match not found";
}
```
OUPUT:
Match found
79
Fetches a key from an array
key(array)
-----------------------
EXAMPLE:
$people=array("Peter","Joe","Glenn","Cleveland");
echo "The key from the current position is: " . key($people);
OUPUT:
The key from the current position is: 0
80
Sorts an associative array in descending order, according to the key
krsort(array,sortingtype);
-----------------------
EXAMPLE:
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
krsort($age);
```
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "
"; } ``` OUPUT: Key=Peter, Value=35 Key=Joe, Value=43 Key=Ben, Value=37
"; } ``` OUPUT: Key=Peter, Value=35 Key=Joe, Value=43 Key=Ben, Value=37
81
Sorts an associative array in ascending order, according to the key
ksort(array,sortingtype);
-----------------------
EXAMPLE:
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
ksort($age);
```
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "
"; } ``` OUPUT: Key=Ben, Value=37 Key=Joe, Value=43 Key=Peter, Value=35
"; } ``` OUPUT: Key=Ben, Value=37 Key=Joe, Value=43 Key=Peter, Value=35
82
Assigns variables as if they were an array
list(var1,var2...)
-----------------------
EXAMPLE:
$my_array = array("Dog","Cat","Horse");
list($a, $b, $c) = $my_array;
echo "I have several animals, a $a, a $b and a $c.";
OUPUT:
I have several animals, a Dog, a Cat and a Horse.
83
Sorts an array using a case insensitive "natural order" algorithm
natcasesort(array)
-----------------------
EXAMPLE:
$temp_files = array("temp15.txt","Temp10.txt",
"temp1.txt","Temp22.txt","temp2.txt");
natsort($temp_files);
echo "Natural order: ";
print_r($temp_files);
echo "
"; natcasesort($temp_files); echo "Natural order case insensitve: "; print_r($temp_files); OUPUT: ``` Natural order: Array ( [0] => Temp10.txt [1] => Temp22.txt [2] => temp1.txt [4] => temp2.txt [3] => temp15.txt ) Natural order case insensitve: Array ( [2] => temp1.txt [4] => temp2.txt [0] => Temp10.txt [3] => temp15.txt [1] => Temp22.txt ) ```
"; natcasesort($temp_files); echo "Natural order case insensitve: "; print_r($temp_files); OUPUT: ``` Natural order: Array ( [0] => Temp10.txt [1] => Temp22.txt [2] => temp1.txt [4] => temp2.txt [3] => temp15.txt ) Natural order case insensitve: Array ( [2] => temp1.txt [4] => temp2.txt [0] => Temp10.txt [3] => temp15.txt [1] => Temp22.txt ) ```
84
Sorts an array using a "natural order" algorithm
natsort(array)
-----------------------
EXAMPLE:
$temp_files = array("temp15.txt","temp10.txt",
"temp1.txt","temp22.txt","temp2.txt");
sort($temp_files);
echo "Standard sorting: ";
print_r($temp_files);
echo "
"; natsort($temp_files); echo "Natural order: "; print_r($temp_files); OUPUT: Standard sorting: Array ( [0] => temp1.txt [1] => temp10.txt [2] => temp15.txt [3] => temp2.txt [4] => temp22.txt ) Natural order: Array ( [0] => temp1.txt [3] => temp2.txt [1] => temp10.txt [2] => temp15.txt [4] => temp22.txt )
"; natsort($temp_files); echo "Natural order: "; print_r($temp_files); OUPUT: Standard sorting: Array ( [0] => temp1.txt [1] => temp10.txt [2] => temp15.txt [3] => temp2.txt [4] => temp22.txt ) Natural order: Array ( [0] => temp1.txt [3] => temp2.txt [1] => temp10.txt [2] => temp15.txt [4] => temp22.txt )
85
Advance the internal array pointer of an array
next(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
```
echo current($people) . "
"; echo next($people); ``` OUPUT: Peter Joe
"; echo next($people); ``` OUPUT: Peter Joe
86
Alias of current()
pos(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
echo pos($people) . "
"; OUPUT: Peter
"; OUPUT: Peter
87
Rewinds the internal array pointer
prev(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
```
echo current($people) . "
"; echo next($people) . "
"; echo prev($people); ``` OUPUT: Peter Joe Peter
"; echo next($people) . "
"; echo prev($people); ``` OUPUT: Peter Joe Peter
88
Creates an array containing a range of elements
range(low,high,step)
-----------------------
EXAMPLE:
$number = range(0,5);
print_r ($number);
OUPUT:
Array ( [0] => 0 [1] => 1 [2] => 2 [3] => 3 [4] => 4 [5] => 5 )
89
Sets the internal pointer of an array to its first element
reset(array)
-----------------------
EXAMPLE:
$people = array("Peter", "Joe", "Glenn", "Cleveland");
```
echo current($people) . "
"; echo next($people) . "
"; ``` echo reset($people); OUPUT: Peter Joe Peter
"; echo next($people) . "
"; ``` echo reset($people); OUPUT: Peter Joe Peter
90
Sorts an indexed array in descending order
rsort(array,sortingtype);
-----------------------
EXAMPLE:
$cars=array("Volvo","BMW","Toyota");
rsort($cars);
$clength=count($cars);
for($x=0;$x";
}
OUPUT:
Volvo
Toyota
BMW
91
Shuffles an array
shuffle(array)
-----------------------
EXAMPLE:
$my_array = array("red","green","blue","yellow","purple");
shuffle($my_array);
print_r($my_array);
OUPUT:
Array ( [0] => red [1] => blue [2] => yellow [3] => green [4] => purple )
Refresh the page to see how shuffle() randomizes the order of the elements in the array.
92
Alias of count()
sizeof(array,mode);
-----------------------
EXAMPLE:
```
$cars=array("Volvo","BMW","Toyota");
echo sizeof($cars);
```
OUPUT:
3
93
Sorts an indexed array in ascending order
sort(array,sortingtype);
-----------------------
EXAMPLE:
$cars=array("Volvo","BMW","Toyota");
sort($cars);
$clength=count($cars);
for($x=0;$x";
}
OUPUT:
BMW
Toyota
Volvo
94
Sorts an array by values using a user-defined comparison function
uasort(array,myfunction);
-----------------------
EXAMPLE:
```
function my_sort($a,$b)
{
if ($a==$b) return 0;
return ($a4,"b"=>2,"c"=>8,d=>"6");
uasort($arr,"my_sort");
```
```
foreach($arr as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "
"; } ``` OUPUT: Key=b, Value=2 Key=a, Value=4 Key=d, Value=6 Key=c, Value=8
"; } ``` OUPUT: Key=b, Value=2 Key=a, Value=4 Key=d, Value=6 Key=c, Value=8
95
Sorts an array by keys using a user-defined comparison function
uksort(array,myfunction);
-----------------------
EXAMPLE:
```
function my_sort($a,$b)
{
if ($a==$b) return 0;
return ($a4,"b"=>2,"c"=>8,d=>"6");
uksort($arr,"my_sort");
```
```
foreach($arr as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "
"; } ``` OUPUT: Key=a, Value=4 Key=b, Value=2 Key=c, Value=8 Key=d, Value=6
"; } ``` OUPUT: Key=a, Value=4 Key=b, Value=2 Key=c, Value=8 Key=d, Value=6
96
Sorts an array using a user-defined comparison function
usort(array,myfunction);
-----------------------
EXAMPLE:
```
function my_sort($a,$b)
{
if ($a==$b) return 0;
return ($a";
}
```
OUPUT:
2
4
6
8
