How to delete text from file using preg_replace() function in PHP ?
Given a file containing some elements and the task is to delete the content of the file using preg_replace() function. The preg_replace() function is searches the string pattern in the file and if string pattern found then it replace with the required string. In simple words it can modify the contents of a file.
Syntax:
preg_replace( $pattern, $replacement, $subject);
Parameters:
- $pattern: It contains the string we have to replace.
- $replacement: It contains the string that will replace the existing string.
- $subject: It contains the main string file where need to remove the string.
We have created a text file named as fruits.txt
fruits.txt
mango
apple
papaya
guava
apple
grapes
mango
apple
Program 1: This program removes all the strings from the given file.
<?php
$a = 'fruits.txt' ;
$b = file_get_contents ( 'fruits.txt' );
echo "File contents before using "
. "preg_replace() function<br>" ;
echo $b ;
echo "<br><br>File contents after using "
. "preg_replace() function<br> " ;
$c = preg_replace( '/[a-z]/' , '' , $b );
echo $c ;
file_put_contents ( $a , $c );
?>
|
Output:
File contents before using preg_replace() function
mango apple papaya guava apple grapes mango apple
File contents after using preg_replace() function
Program 2: This program deletes a specific content from the file using preg_replace() function.
<?php
$a = 'fruits.txt' ;
$b = file_get_contents ( 'fruits.txt' );
echo "File contents before using "
+ "preg_replace() function<br>" ;
echo $b ;
echo "<br><br>File contents after using "
+ "preg_replace() function<br>" ;
$c = preg_replace( '/[a]/' , '' , $b );
echo $c ;
file_put_contents ( $a , $c );
?>
|
Output:
File contents before using preg_replace() function
mango apple papaya guava apple grapes mango apple
File contents after using preg_replace() function
mngo pple ppy guv pple grpes mngo pple
Program 3: This program deletes the entire word from the file.
<?php
$a = 'fruits.txt' ;
$b = file_get_contents ( 'fruits.txt' );
echo "File contents before using "
. "preg_replace() function<br>" ;
echo $b ;
echo "<br><br>File contents after using "
. "preg_replace() function<br>" ;
$c = preg_replace( '/apple/' , '' , $b );
echo $c ;
file_put_contents ( $a , $c );
?>
|
Output:
File contents before using preg_replace() function
mango apple papaya guava apple grapes mango apple
File contents after using preg_replace() function
mango papaya guava grapes mango
Last Updated :
14 Feb, 2020
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