String split and explode in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to split the string into an array using a space.

PHP

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

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

A" "

B","

C"-"

D";"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a comma instead of a space as delimiter.

Forgetting to put the delimiter inside quotes.

The explode function splits a string by the given delimiter. Here, the delimiter is a space " ".

2fill in blank

medium

Complete the code to split the string by commas.

PHP

<?php
$csv = "red,green,blue";
$colors = explode([1], $csv);
print_r($colors);
?>

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

A","

B" "

C";"

D"|"

Attempts:

3 left

💡 Hint

Common Mistakes

Using space as delimiter when the string uses commas.

Not putting the delimiter in quotes.

The string contains colors separated by commas, so the delimiter for explode should be a comma ",".

3fill in blank

hard

Fix the error in the code to split the string by dash.

PHP

<?php
$dates = "2023-06-15";
$parts = explode([1], $dates);
print_r($parts);
?>

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

A"_"

B"-"

C'-'

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using the dash without quotes causes a syntax error.

Using the wrong delimiter character.

The delimiter must be a string inside quotes. Using "-" or '-' is correct. Option C is missing quotes and causes an error.

4fill in blank

hard

Fill both blanks to create an array of words longer than 3 letters.

PHP

<?php
$sentence = "I love coding in PHP";
$words = explode([1], $sentence);
$longWords = array_filter($words, fn($word) => strlen($word) [2] 3);
print_r($longWords);
?>

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

A" "

B>

C<

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Using comma as delimiter instead of space.

Using less than operator instead of greater than.

The string is split by space " ". The filter keeps words with length greater than 3 using >.

5fill in blank

hard

Fill all three blanks to create an associative array of words and their lengths for words longer than 2 letters.

PHP

<?php
$text = "apple banana cat dog";
$result = [];
foreach(explode(" ", $text) as [3]) {
    if(strlen([3]) > 2) {
        $result[[1]] = [2];
    }
}
print_r($result);
?>

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

A$word

Bstrlen($word)

D$text

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names.

Confusing keys and values in the array.

We loop over each $word from exploding the string by space. The key is the word $word, the value is its length strlen($word).

Practice

1. What does the PHP function explode() do?

easy

A. It replaces parts of a string with another string.

B. It joins array elements into a string.

C. It counts the number of characters in a string.

D. It splits a string into an array using a delimiter.

Solution

1. Step 1: Understand the purpose of explode()

   The explode() function takes a string and splits it into pieces based on a delimiter.

2. Step 2: Recognize the output type

   It returns an array containing the split parts of the original string.

3. Final Answer:

   It splits a string into an array using a delimiter. -> Option D

4. Quick Check:

   explode() = split string to array [OK]

Hint: explode() breaks strings into arrays by delimiter [OK]

Common Mistakes:

• Confusing explode() with implode() which joins arrays
• Thinking explode() returns a string instead of an array
• Assuming explode() modifies the original string

2. Which of the following is the correct syntax to split the string 'apple,banana,orange' by commas using explode()?

easy

A. explode(' ', 'apple,banana,orange')

B. explode('apple,banana,orange', ',')

C. explode(',', 'apple,banana,orange')

D. explode('apple', 'banana,orange')

Solution

1. Step 1: Identify explode() parameter order

   The first parameter is the delimiter (separator), the second is the string to split.

2. Step 2: Match parameters to the example

   To split by commas, delimiter is ',' and string is 'apple,banana,orange'. So syntax is explode(',', 'apple,banana,orange').

3. Final Answer:

   explode(',', 'apple,banana,orange') -> Option C

4. Quick Check:

   explode(delimiter, string) = explode(',', 'apple,banana,orange') [OK]

Hint: Delimiter is first, string second in explode() [OK]

Common Mistakes:

• Swapping the order of parameters
• Using wrong delimiter like space instead of comma
• Passing parts of string as delimiter

3. What is the output of the following PHP code?

$str = "one,two,three,four";
$result = explode(",", $str, 3);
print_r($result);

medium

A. Array ( [0] => one [1] => two [2] => three,four )

B. Array ( [0] => one [1] => two [2] => three )

C. Array ( [0] => one,two [1] => three [2] => four )

D. Array ( [0] => one [1] => two [2] => three [3] => four )

Solution

1. Step 1: Understand explode() with limit parameter

   The third parameter limits the number of pieces. Here, limit=3 means maximum 3 parts.

2. Step 2: Apply limit to splitting

   The string splits at first two commas: 'one', 'two', and the rest 'three,four' stays as last part.

3. Final Answer:

   Array ( [0] => one [1] => two [2] => three,four ) -> Option A

4. Quick Check:

   explode(',', string, 3) limits to 3 parts [OK]

Hint: Limit splits into max parts; last part keeps rest [OK]

Common Mistakes:

• Ignoring the limit parameter effect
• Expecting all parts split regardless of limit
• Confusing array keys or values

4. Identify the error in this PHP code snippet:

$data = "red|green|blue";
$colors = explode($data, "|");
print_r($colors);

medium

A. The delimiter "|" is invalid in explode().

B. The delimiter and string parameters are swapped in explode().

C. explode() cannot split strings with pipe characters.

D. print_r() cannot print arrays.

Solution

1. Step 1: Check explode() parameter order

   explode() expects delimiter first, then the string to split.

2. Step 2: Analyze given code

   Code uses explode($data, "|"), which swaps parameters incorrectly.

3. Final Answer:

   The delimiter and string parameters are swapped in explode(). -> Option B

4. Quick Check:

   explode(delimiter, string) correct order [OK]

Hint: Delimiter always first, string second in explode() [OK]

Common Mistakes:

• Swapping parameters causing wrong output or errors
• Thinking delimiter must be a letter only
• Assuming print_r() can't print arrays

5. You have a string "name:age:city:country". You want to split it into exactly 3 parts where the last part contains everything after the second colon. Which explode() call achieves this?

hard

A. explode(':', $string, 3)

B. explode(':', $string, 2)

C. explode(':', $string, 4)

D. explode(':', $string)

Solution

1. Step 1: Understand the limit parameter in explode()

   Limit defines max number of parts. If limit=3, explode splits at first two delimiters, last part has rest.

2. Step 2: Apply to given string

   With limit=3, parts are: 'name', 'age', and 'city:country' combined as last part.

3. Final Answer:

   explode(':', $string, 3) -> Option A

4. Quick Check:

   Limit 3 splits into 3 parts, last part keeps rest [OK]

Hint: Use limit=3 to get 3 parts, last part keeps remaining string [OK]

Common Mistakes:

• Using limit=2 which gives only 2 parts
• Using no limit which splits all parts
• Confusing limit with number of delimiters