PHP String Exercises: Replace the first word with another word

Last update on December 20 2024 10:19:23 (UTC/GMT +8 hours)

Write a PHP script to replace the first 'the' of the following string with 'That'.

Sample date: 'the quick brown fox jumps over the lazy dog.'

Visual Presentation:

Sample Solution:

PHP Code:

<?php
// Define a string variable containing the phrase "the quick brown fox jumps over the lazy dog."
$str = 'the quick brown fox jumps over the lazy dog.';
// Use preg_replace function to replace the first occurrence of the word 'the' with 'That' in the string.
// The pattern '/the/' is a regular expression pattern matching the word 'the'.
// 'That' is the replacement string.
// The '1' parameter specifies that only the first occurrence of 'the' should be replaced.
echo preg_replace('/the/', 'That', $str, 1)."\n"; 
?>

Output:

That quick brown fox jumps over the lazy dog.

Explanation:

In the exercise above,

• <?php: This tag indicates the beginning of PHP code.
• $str = 'the quick brown fox jumps over the lazy dog.';: This line initializes a string variable $str with the value 'the quick brown fox jumps over the lazy dog.'.
• echo preg_replace('/the/', 'That', $str, 1)."\n";:
• preg_replace() is a PHP function used for performing a regular expression search and replace.
• /the/ is a regular expression pattern that matches the word 'the' in the string.
• 'That' is the replacement string that replaces the matched word.
• $str is the input string on which the replacement operation is performed.
• 1 is the fourth parameter, which specifies the maximum number of replacements to be made. In this case, it's set to 1, meaning only the first occurrence of 'the' will be replaced.
• echo is used to output the replacement result.
• ."\n" adds a newline character at the end of the output for better formatting.

Flowchart:

PHP Code Editor:

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