How to Replace a Substring in a String using Regular Expression in JavaScript - Step by Step Examples

How to Replace a Substring in a String using Regular Expression in JavaScript ?

Answer

To replace all occurrences of a substring in a string using regular expression in JavaScript, you can use the replace method with a regex pattern and the g flag.

✐ Examples

1 Replace Substring "Hello" with "Hi"

In this example,

We create a string named str.
We use the replace method on str with a regex pattern matching "Hello" and replace it with "Hi" using the g flag.
The replace method returns a new string with all occurrences replaced.
Finally, we print the modified string.

JavaScript Program

let str = "Hello World Hello";
let newStr = str.replace(/Hello/g, "Hi");
console.log(newStr);

Output

Hi World Hi

2 Replace Digits with 'Y'

In this example,

We create a string named str.
We use the replace method on str with a regex pattern matching digits (\d) and replace them with 'Y' using the g flag.
The replace method returns a new string with all occurrences replaced.
Finally, we print the modified string.

JavaScript Program

let str = "Hello123World789";
let newStr = str.replace(/\d/g, "Y");
console.log(newStr);

Output

HelloYYYWorldYYY

Summary

In this tutorial, we learned How to Replace a Substring in a String using Regular Expression in JavaScript language with well detailed examples.

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How to Replace a Substring in a String using Regular Expression in JavaScript - Step by Step Examples

How to Replace a Substring in a String using Regular Expression in JavaScript ?

Answer

✐ Examples

1 Replace Substring "Hello" with "Hi"

JavaScript Program

Output

2 Replace Digits with 'Y'

JavaScript Program

Output

Summary

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