Dart – Replace Substring in String

To replace all occurrences of a substring in a string with new substring, use String.replaceAll() method.

Syntax

The syntax of replaceAll() method is:

String.replaceAll(Pattern pattern, String newSubString)

The method returns a new string with all string matchings of given pattern replaced with newSubString. You can also give a string for pattern.

Examples

Replace Substring in String

In this example, we will take a string str, and replace 'Hello' with 'Hi' in the string str.

Dart Program

void main(){
	
	String str = 'Hello TutorialKart. Hello User.';
	
	//replace subString
	String result = str.replaceAll('Hello', 'Hi');
	
	print(result);
}

Output

Hi TutorialKart. Hi User.

Now, let us take a string and replace the substring 'Ola' with 'Hi' in the string. But, the string does not contain 'Ola'. Let us see what happens.

Dart Program

void main(){
	
	String str = 'Hello TutorialKart. Hello User.';
	
	//replace subString
	String result = str.replaceAll('Ola', 'Hi');
	
	print(result);
}

Output

Hello TutorialKart. Hello User.

Since there is no match for the provided pattern, copy of the original string is returned by replaceAll().

Chaining replaceAll() method

You can chain replaceAll() method. In this example, we will chain replaceAll() method. Please observe the following Dart program.

Dart Program

void main(){
	
	String str = 'Hello TutorialKart. Hello User.';
	
	//replaceAll() chaining
	String result = str.replaceAll('Hello', 'Hi').replaceAll('User', 'Client');
	
	print(result);
}

Output

Hi TutorialKart. Hi Client.

First replaceAll() replaces 'Hello' with 'Hi', and then on this resulting string, second replaceAll() replaces 'User' with 'Client'.

Conclusion

In this Dart Tutorial, we learned how to replace all occurrences of a substring with another, in a given string, using String.replaceAll() method.