Implementing find and replace functionality in PHP

In this session today we will be implementing find and replace functionality in php.Here we will be creating a form which will have an text area , search box , replace box and an find and replace button .

• For implementing find and replace functionality in php follow the steps given below :

1. First of all download and install xampp server in your machine .
2. Let’s begin with creating a form .
3. Go to Start->All Programs->XAMPP->XAMPP htdocs folder as shown below in the image ..




4. In htdocs folder create a new folder and lets name the folder as search.




5. Inside the search folder create a new file say index.php.




6. Open the index.php file with any text editor for example Notepad++ and write the following code for the form creation:

<form action="index.php" method="POST">
    <label>Type your Text Here</label><br><br>
    <textarea name="textarea" cols="40" rows="10"></textarea><br><br>
    Search For Text<br>
    <input type="text" name="search"><br><br>
    Replace Text With<br>
    <input type="text" name="replace"><br><br>
    <input type="submit" value="Find and Replace">
</form>

7. Here is the screen shot of the code :



8. Now open up your browser and enter the following url http://localhost/Search/
9. Thus you will have the following output :




10. Now let’s write the logic for find and replace .
11. Now in the same index.php file add the following code.

<?php
//This will will take all the values from textarea and text from the html form
if(isset($_POST['textarea']) && isset($_POST['search']) && isset($_POST['replace']))
{
    
}
?>

12. Here is the screen shot for it :




13. Now inside if statement take three variables which will store the values from the post variable and also perform validation checks on it.

//stores the value from the post variables
     $text = $_POST['textarea'];
     $search = $_POST['search'];
    $replace = $_POST['replace'];
    
    //validation is made to check if all the fields are entered
    if(!empty($text) && !empty($search) && !empty($replace)){
    
    }else{
        echo 'Please fill all the fields';
    }

14. Here is the screen shot for it..




15. So now if you run your programme and forget to fill any of the field it will pop-up an message which will say ” Please fill all the fields “.




16. Now take two variable :

    //This is to point to the string characters to search for the matching pair
    $offset = NULL;
    //This variable is used to store the length of the search string 
    $searchLength = strlen($search);

17. Here is the screen shot of the code :




18. Now let’s take one while loop inside the nested if statements so add the code as follows :

//The while loop takes three parameters 
//first parameter will take the current text 
//second parameter will take the text which wants to search
//third parameter will take the character where the search is matched
while ($stringPostion = strpos($text, $search, $offset))
                {
                    //This will check if we have visited all the characters of the string
                    $offset = $stringPostion + $searchLength;
                    
                }

19. Screen shot is shown below :




20. Now add function to replace the string which is found

      //This function takes four parameters 
                    //First param checks the string to check
                    //second param replaces the find string
                    //third param specify from where the string replacing should start
                    //fourth param specify how many character should be replaced

                    $text = substr_replace($text, $replace, $stringPostion, $searchLength);

21. Screen shot is given below :




22. Now add the following line of code after the while loop to display the string in the replaced version.

//This will display the string which appears after replacement
echo $text;

23. Here is the screen shot for it :




24. Now here is the complete code for implementing find and replace functionality in php .

<form action="index.php" method="POST">
    <label>Type your Text Here</label><br><br>
    <textarea name="textarea" cols="40" rows="10"></textarea><br><br>
    Search For Text<br>
    <input type="text" name="search"><br><br>
    Replace Text With<br>
    <input type="text" name="replace"><br><br>
    <input type="submit" value="Find and Replace">
</form>

<?php
//This will will take all the values from textarea and text from the html form
if(isset($_POST['textarea']) && isset($_POST['search']) && isset($_POST['replace']))
{
    //stores the value from the post variables
     $text = $_POST['textarea'];
     $search = $_POST['search'];
    $replace = $_POST['replace'];
    //This is to point to the string characters to search for the matching pair
    $offset = NULL;
    //This variable is used to store the length of the search string 
    $searchLength = strlen($search);
    
    //validation is made to check if all the fields are entered
    if(!empty($text) && !empty($search) && !empty($replace)){
        
        //The while loop takes three parameters 
        //first parameter will take the current text 
        //second parameter will take the text which wants to search
        //third parameter will take the character where the search is matched
        while ($stringPostion = strpos($text, $search, $offset))
                {
                    //This will check if we have visited all the characters of the string
                    $offset = $stringPostion + $searchLength;
                    //This function takes four parameters 
                    //First param checks the string to check
                    //second param replaces the find string
                    //third param specify from where the string replacing should start
                    //fourth param specify how many character should be replaced
                    $text = substr_replace($text, $replace, $stringPostion, $searchLength);
                }
                echo $text;
    }else{
        echo 'Please fill all the field';
    }
}

?>

25. Now open up the browser and enter the following url localhost/Search/index.php and you will have the following output :




26. Now type the Following text in your text area as follows Android is used by Apple
27. Corresponding to your search field write Apple
28. Corresponding to your replace field write Google
29. After filling up the respective fields you will have the following view of your window:




30. So now when you click on the find and replace button you will see the following output :




31. Thus ,we have successfully learnt implementing find and replace functionality in php.