Array Exercises (PHP)

array.md

Array Exercises (PHP)

Questions

1. If you have an array $a = array( 0, 1, 2, 3, 4 );, how do you extract the value 3 from the array?

2. If you have an array $a = array( "zero"=>0, "one"=>1, "two"=>2, "three"=>3, "four"=>4 );, how do you extract the value 3 from the array?

3. If you have the following array, how do you extract the value 3 from the array?

   $a = array(
       array(
           0,
           1
       ),
       array(
           2,
           array(
               3
           )
       )
   );
   

4. If you have the following array, how do you extract the value 3 from the array?

   $a = array(
       "a"=>array(
           "b"=>0,
           "c=>1
       ),
       "b"=>array(
           "e"=>2,
           "o"=>array(
               "b"=>3
           )
       )
   );
   

5. Create a new array with each comma-separated value as its own array element from the string $a = "a,b,c,d,e,f".

6. With the result array from 5, create a new array where each element is both key and value. In other words, the result should be:

   array(
       "a"=>"a",
       "b"=>"b",
       "c"=>"c",
       "d"=>"d",
       "e"=>"e"
   )
   

7. You have two arrays like the following. One contains field labels, the other contains field values. Write a program to output the third array.

   $keys = array(
       "field1"=>"first",
       "field2"=>"second",
       "field3"=>"third"
   );
   $values = array(
       "field1value"=>"dinosaur",
       "field2value"=>"pig",
       "field3value"=>"platypus"
   );
   // want to output
   $keysAndValues = array(
       "first"=>"dinosaur",
       "second"=>"pig",
       "third"=>"platypus"
   );
   

8. You have an array of transactions, each of which has a debit and credit amount. Find the absolute value of the transaction amount (i.e. abs( debit - credit )) and add it as a new key=>value pair to each transaction.

   $transactions = array(
       array(
           "debit"=>2,
           "credit"=>3
       ),
       array(
           "debit"=>15,
           "credit"=>14
       )
   );
   // outputs
   $transactions = array(
       array(
           "debit"=>2,
           "credit"=>3,
           "amount"=>1
       ),
       array(
           "debit"=>15,
           "credit"=>14,
           "amount"=>1
       )
   );
   

9. Find the sum of this array of numbers $a = array( 0, 1, 2, 3, 4, 5, 6 );.