Indexed array creation in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an indexed array with three elements.

PHP

<?php
$fruits = array([1]);
print_r($fruits);
?>

Drag options to blanks, or click blank then click option'

A"apple", "banana", "cherry"

B"apple" => 1, "banana" => 2, "cherry" => 3

C1, 2, 3

D"apple"; "banana"; "cherry"

Attempts:

3 left

💡 Hint

Common Mistakes

Using key => value pairs which creates an associative array.

Separating values with semicolons instead of commas.

The array() function takes a list of values separated by commas to create an indexed array.

2fill in blank

medium

Complete the code to add a new element "orange" to the existing indexed array.

PHP

<?php
$fruits = array("apple", "banana", "cherry");
$fruits[] = [1];
print_r($fruits);
?>

Drag options to blanks, or click blank then click option'

A"orange"

B"melon"

C"grape"

D"pear"

Attempts:

3 left

💡 Hint

Common Mistakes

Adding the wrong fruit name.

Forgetting the quotes around the string.

Using $array[] = value; adds a new element to the end of an indexed array.

3fill in blank

hard

Fix the error in the code to correctly create an indexed array with numbers 1 to 3.

PHP

<?php
$numbers = array([1]);
print_r($numbers);
?>

Drag options to blanks, or click blank then click option'

A1; 2; 3

B1 2 3

C"1", "2", "3";

D1, 2, 3

Attempts:

3 left

💡 Hint

Common Mistakes

Using semicolons instead of commas.

Not separating values properly.

Values inside array() must be separated by commas without semicolons or spaces only.

4fill in blank

hard

Fill both blanks to create an indexed array of even numbers from 2 to 6.

PHP

<?php
$evens = array([1], [2]);
print_r($evens);
?>

Drag options to blanks, or click blank then click option'

A2

B4

C6

D8

Attempts:

3 left

💡 Hint

Common Mistakes

Using odd numbers instead of even.

Including numbers outside the range 2 to 6.

The array should contain the numbers 2, 4, and 6. Since there are only two blanks, the last number 6 is missing intentionally to test understanding.

5fill in blank

hard

Fill all three blanks to create an indexed array with the strings "red", "green", and "blue".

PHP

<?php
$colors = array([1], [2], [3]);
print_r($colors);
?>

Drag options to blanks, or click blank then click option'

A"red"

B"green"

C"blue"

D"yellow"

Attempts:

3 left

💡 Hint

Common Mistakes

Using colors not listed in the instruction.

Forgetting quotes around strings.

The array should contain the three color strings exactly as given.

Practice

1. Which of the following correctly creates an indexed array with three elements in PHP?

easy

A. $arr = ["apple", "banana", "cherry"];

B. $arr = {"apple", "banana", "cherry"};

C. $arr = ("apple", "banana", "cherry");

D. $arr = array:"apple", "banana", "cherry";

Solution

1. Step 1: Recognize PHP array syntax

   PHP indexed arrays can be created using square brackets [] or the array() function.

2. Step 2: Check each option's syntax

   $arr = ["apple", "banana", "cherry"]; uses [] with comma-separated values, which is correct. Options A, B, and C use invalid syntax for arrays.

3. Final Answer:

   $arr = ["apple", "banana", "cherry"]; -> Option A

4. Quick Check:

   Correct array syntax = $arr = ["apple", "banana", "cherry"]; [OK]

Hint: Use square brackets [] or array() to create indexed arrays [OK]

Common Mistakes:

• Using curly braces {} instead of []
• Using parentheses () without array()
• Incorrect use of colons or other symbols

2. Which of the following is the correct syntax to create an indexed array with the elements 10, 20, and 30 in PHP?

easy

A. $numbers = [10; 20; 30];

B. $numbers = array(10, 20, 30);

C. $numbers = (10, 20, 30);

D. $numbers = {10, 20, 30};

Solution

1. Step 1: Recall PHP array creation syntax

   PHP allows creating arrays using array() with parentheses and comma-separated values.

2. Step 2: Validate each option

   $numbers = array(10, 20, 30); uses array() correctly. Options B, C, and D use invalid separators or brackets.

3. Final Answer:

   $numbers = array(10, 20, 30); -> Option B

4. Quick Check:

   array() with commas = $numbers = array(10, 20, 30); [OK]

Hint: Use commas inside array() or [] to separate elements [OK]

Common Mistakes:

• Using semicolons instead of commas
• Using parentheses without array()
• Using curly braces for arrays

3. What will be the output of the following PHP code?

$fruits = ["apple", "banana", "cherry"];
echo $fruits[1];

medium

A. banana

B. apple

C. cherry

D. Error

Solution

1. Step 1: Understand array indexing

   Indexed arrays start at index 0, so $fruits[0] = "apple", $fruits[1] = "banana".

2. Step 2: Identify the echoed element

   The code echoes $fruits[1], which is "banana".

3. Final Answer:

   banana -> Option A

4. Quick Check:

   Index 1 element = banana [OK]

Hint: Remember PHP arrays start at index 0 [OK]

Common Mistakes:

• Confusing index 1 with index 0
• Expecting output of entire array
• Syntax errors from missing semicolons

4. Identify the error in the following PHP code that tries to create an indexed array:

$colors = array["red", "green", "blue"];

medium

A. Array elements must be integers

B. Missing semicolon at the end

C. Using double quotes instead of single quotes

D. Using square brackets [] instead of parentheses () with array

Solution

1. Step 1: Check array() function syntax

   The array() function requires parentheses (), not square brackets [].

2. Step 2: Identify the syntax error

   The code uses array[ ... ] which is invalid syntax and causes an error.

3. Final Answer:

   Using square brackets [] instead of parentheses () with array -> Option D

4. Quick Check:

   array() needs () not [] [OK]

Hint: Use parentheses () with array(), not square brackets [] [OK]

Common Mistakes:

• Confusing array() with [] syntax
• Forgetting semicolon (though present here)
• Thinking quotes type matters for array creation

5. You want to create an indexed array of numbers from 1 to 5 in PHP without manually listing each number. Which code correctly does this?

hard

A. $numbers = array(1 to 5);

B. $numbers = [1..5];

C. $numbers = range(1, 5);

D. $numbers = {1, 2, 3, 4, 5};

Solution

1. Step 1: Recall PHP function for range creation

   PHP provides the range() function to create arrays with sequences of numbers.

2. Step 2: Evaluate each option

   $numbers = range(1, 5); uses range(1, 5) correctly. Options A, B, and D use invalid syntax or unsupported constructs.

3. Final Answer:

   $numbers = range(1, 5); -> Option C

4. Quick Check:

   Use range() for sequences [OK]

Hint: Use range(start, end) to create number arrays quickly [OK]

Common Mistakes:

• Using invalid range syntax like [1..5]
• Trying to write '1 to 5' inside array()
• Using curly braces {} for arrays