PHP arrays - Exercises, Practice, Solution

PHP arrays [59 exercises with solution]

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1. $color = array('white', 'green', 'red', 'blue', 'black');
Write a script which will display the following string -
"The memory of that scene for me is like a frame of film forever frozen at that moment: the red carpet, the green lawn, the white house, the leaden sky. The new president and his first lady. - Richard M. Nixon"
and the words 'red', 'green' and 'white' will come from $color.

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2. $color = array('white', 'green', 'red'')
Write a PHP script which will display the colors in the following way :
Output :
white, green, red,

• green
• red
• white

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3. $ceu = array( "Italy"=>"Rome", "Luxembourg"=>"Luxembourg", "Belgium"=> "Brussels", "Denmark"=>"Copenhagen", "Finland"=>"Helsinki", "France" => "Paris", "Slovakia"=>"Bratislava", "Slovenia"=>"Ljubljana", "Germany" => "Berlin", "Greece" => "Athens", "Ireland"=>"Dublin", "Netherlands"=>"Amsterdam", "Portugal"=>"Lisbon", "Spain"=>"Madrid", "Sweden"=>"Stockholm", "United Kingdom"=>"London", "Cyprus"=>"Nicosia", "Lithuania"=>"Vilnius", "Czech Republic"=>"Prague", "Estonia"=>"Tallin", "Hungary"=>"Budapest", "Latvia"=>"Riga", "Malta"=>"Valetta", "Austria" => "Vienna", "Poland"=>"Warsaw") ;

Create a PHP script which displays the capital and country name from the above array $ceu. Sort the list by the capital of the country.

Sample Output :
The capital of Netherlands is Amsterdam 
The capital of Greece is Athens 
The capital of Germany is Berlin 
- - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - - - - - - -

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4. $x = array(1, 2, 3, 4, 5);
Delete an element from the above PHP array. After deleting the element, integer keys must be normalized.
Sample Output :
array(5) { [0]=> int(1) [1]=> int(2) [2]=> int(3) [3]=> int(4) [4]=> int(5) } 
array(4) { [0]=> int(1) [1]=> int(2) [2]=> int(3) [3]=> int(5) }

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5. $color = array(4 => 'white', 6 => 'green', 11=> 'red');
Write a PHP script to get the first element of the above array.
Expected result : white

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6. Write a PHP script which decodes the following JSON string.
Sample JSON code :
{"Title": "The Cuckoos Calling",
"Author": "Robert Galbraith",
"Detail": {
"Publisher": "Little Brown"
}}
Expected Output :
Title : The Cuckoos Calling
Author : Robert Galbraith
Publisher : Little Brown

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7. Write a PHP script that inserts a new item in an array in any position.
Expected Output :
Original array : 
1 2 3 4 5 
After inserting '$' the array is :
1 2 3 $ 4 5

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8. Write a PHP script to sort the following associative array :
array("Sophia"=>"31","Jacob"=>"41","William"=>"39","Ramesh"=>"40") in
a) ascending order sort by value
b) ascending order sort by Key
c) descending order sorting by Value
d) descending order sorting by Key

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9. Write a PHP script to calculate and display average temperature, five lowest and highest temperatures.
Recorded temperatures : 78, 60, 62, 68, 71, 68, 73, 85, 66, 64, 76, 63, 75, 76, 73, 68, 62, 73, 72, 65, 74, 62, 62, 65, 64, 68, 73, 75, 79, 73
Expected Output :
Average Temperature is : 70.6 
List of seven lowest temperatures : 60, 62, 63, 63, 64, 
List of seven highest temperatures : 76, 78, 79, 81, 85,

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10. Write a PHP program to sort an array of positive integers using the Bead-Sort Algorithm.
According to Wikipedia "Bead-sort is a natural sorting algorithm, developed by Joshua J. Arulanandham, Cristian S. Calude and Michael J. Dinneen in 2002. Both digital and analog hardware implementations of bead sort can achieve a sorting time of O(n); however, the implementation of this algorithm tends to be significantly slower in software and can only be used to sort lists of positive integers".

Input array : Array ( [0] => 5 [1] => 3 [2] => 1 [3] => 3 [4] => 8 [5] => 7 [6] => 4 [7] => 1 [8] => 1 [9] => 3 )
Expected Result : Array ( [0] => 8 [1] => 7 [2] => 5 [3] => 4 [4] => 3 [5] => 3 [6] => 3 [7] => 1 [8] => 1 [9] => 1 )

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11. Write a PHP program to merge (by index) the following two arrays.
Sample arrays :
$array1 = array(array(77, 87), array(23, 45));
$array2 = array("w3resource", "com");
Expected Output :

Array  
(      
[0] => Array          
(              
[0] => w3resource              
[1] => 77              
[2] => 87          
)        
[1] => Array          
(              
[0] => com              
[1] => 23              
[2] => 45          
)    
)

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12. Write a PHP function to change the following array's all values to upper or lower case.
Sample arrays :
$Color = array('A' => 'Blue', 'B' => 'Green', 'c' => 'Red');
Expected Output :
Values are in lower case.
Array ( [A] => blue [B] => green [c] => red ) 
Values are in upper case.
Array ( [A] => BLUE [B] => GREEN [c] => RED )

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13. Write a PHP script which displays all the numbers between 200 and 250 that are divisible by 4.
Note : Do not use any PHP control statement.
Expected Output : 200,204,208,212,216,220,224,228,232,236,240,244,248

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14. Write a PHP script to get the shortest/longest string length from an array.
Sample arrays : ("abcd","abc","de","hjjj","g","wer")
Expected Output : The shortest array length is 1. The longest array length is 4.

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15. Write a PHP script to generate unique random numbers within a range.
Sample Range : (11, 20)
Sample Output : 17 16 13 20 14 19 18 15 11 12

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16. Write a PHP script to get the largest key in an array.
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17. Write a PHP function that returns the lowest integer that is not 0.
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18. Write a PHP function to floor decimal numbers with precision.
Note: Accept three parameters number, precision, and $separator
Sample Data :
1.155, 2, "."
100.25781, 4, "."
-2.9636, 3, "."

Expected Output :
1.15
100.2578
-2.964

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19. Write a PHP script to print "second" and Red from the following array.
Sample Data :
$color = array ( "color" => array ( "a" => "Red", "b" => "Green", "c" => "White"),
"numbers" => array ( 1, 2, 3, 4, 5, 6 ),
"holes" => array ( "First", 5 => "Second", "Third"));

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20. Write a PHP function to sort an array according to another array acting as a priority list.
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21. Write a PHP function to sort subnets.
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22. Write a PHP script to sort the following array by the day (page_id) and username.
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23. Write a PHP program to sort a multi-dimensional array set by a specific key.
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24. Write a PHP script to sort an array using case-insensitive natural ordering.
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25. Write a PHP function to sort entity letters.
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26. Write a PHP function to shuffle an associative array, preserving key, value pairs.
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27. Write a PHP function to generate a random password (contains uppercase, lowercase, numeric and other) using shuffle() function.
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28. Write a PHP script to sort an array in reverse order (highest to lowest).

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29. Write a PHP program to generate an array with a range taken from a string.
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30. Write a PHP program to create a letter range with arbitrary length.
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31. Write a PHP program to get the index of the highest value in an associative array.
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32. Write a PHP program to get the extension of a file.
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33. Write a PHP function to search a specified value within the values of an associative array.
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34. Write a PHP program to sort an associative array (alphanumeric with case-sensitive data) by values.
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35. Write a PHP script to trim all the elements in an array using array_walk function.
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36. Write a PHP script to lower-case and upper-case, all elements in an array.
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37. Write a PHP script to count the total number of times a specific value appears in an array.
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38. Write a PHP function to create a multidimensional unique array for any single key index.
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39. Write a PHP program to remove duplicate values from an array which contains only strings or only integers.
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40. Write a PHP program to get a sorted array without preserving the keys.
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41. Write a PHP program to identify the email addresses which are not unique.
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42. Write a PHP function to find unique values from multidimensional arrays and flatten them in zero depth.
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43. Write a PHP script to merge two commas separated lists with unique value only.
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44. Write a PHP a function to remove a specified, duplicate entry from an array.
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45. Write a PHP script to do a multi-dimensional difference, i.e. returns values of the first array that are not in the second array.
Note : Use array_udiff() function.
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46. Write a PHP function to check whether all array values are strings or not.
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47. Write a PHP function to get an array with the first key and value.

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48. Write a PHP function to set union of two arrays.
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49. Write a PHP script to get an array containing all the entries of an array which have the keys that are present in another array.
Test Data : 1st array : ('c1' => 'Red', 'c2' => 'Green', 'c3' => 'White', c4 => 'Black')
2nd array : ('c2', 'c4')
Output :
Array
(
[c2] => Green
[c4] => Black
)

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50. Write a PHP script to get the last value of an array without affecting the pointer.
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51. Write a PHP program to filter out some elements with certain key-names.
Test Data :
1st array : ('c1' => 'Red', 'c2' => 'Green', 'c3' => 'White', c4 => 'Black')
2nd array : ('c2', 'c4')
Output :
Array
(
[c1] => Red
[c3] => White
)

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52. Write a PHP function to filter a multi-dimensional array. The function will return those items that will match with the specified value.
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53. Write a PHP script to delete a specific value from an array using array_filter() function.
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54. Write a PHP script to remove all white spaces in an array.
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55. Write a PHP function to convert a string to an array (trimming every line and remove empty lines).
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56. Write a PHP script to create a two-dimensional array (4x4), initialized to 10.
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57. Write a PHP function to compares two multidimensional arrays and returns the difference.
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58. Write a PHP script to combine (using one array for keys and another for its values) the following two arrays.
('x', 'y', 'y'), (10, 20, 30)
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59. Write a PHP program to create a range like the following array.
Array
(
[20] => 2
[21] => 3
[22] => 4
[23] => 5
[24] => 6
[25] => 7
)

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