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
