PHP How to add backslash inside array of strings?

To add backslashes inside an array of strings, you can use json_encode() function twice. This technique is useful when you need to escape quotes within JSON strings for JavaScript or database storage.

Let's say the following is our array −

$value = [
    "ADD", "REMOVE", "SELECT", "MODIFY"
];

We want the output with backslashes inside array of strings i.e −

"["ADD","REMOVE","SELECT","MODIFY"]"

Using Double json_encode()

The PHP code is as follows −

<?php
    $value = [
        "ADD", "REMOVE", "SELECT", "MODIFY"
    ];
    echo json_encode(json_encode($value)) . "<br>";
?>

This will produce the following output −

"["ADD","REMOVE","SELECT","MODIFY"]"

How It Works

The first json_encode() converts the PHP array to JSON format. The second json_encode() escapes the quotes and wraps the entire string in quotes, adding the necessary backslashes before internal quotes.

Alternative Method Using addslashes()

You can also achieve similar results using addslashes() function −

<?php
    $value = [
        "ADD", "REMOVE", "SELECT", "MODIFY"
    ];
    $jsonString = json_encode($value);
    echo '"' . addslashes($jsonString) . '"';
?>

"["ADD","REMOVE","SELECT","MODIFY"]"

Conclusion

Double json_encode() is the most efficient method to add backslashes inside array strings. This technique is particularly useful when preparing data for JavaScript or escaping JSON strings for database storage.