The replaceAll() method replaces each substring that matches the regex of the string with the specified text.
Example
Syntax of replaceAll()
The syntax of the replaceAll() method is:
string.replaceAll(String regex, String replacement)
Here, string is an object of the String class.
replaceAll() Parameters
The replaceAll() method takes two parameters.
- regex - a regex (can be a typical string) that is to be replaced
- replacement - matching substrings are replaced with this string
replaceAll() Return Value
The replaceAll() method
- returns a new string where each occurrence of the matching substring is replaced with the replacement string.
Example 1: Java String replaceAll()
In the above example, "\\d+" is a regular expression that matches one or more digits. To learn more, visit Java regex.
Escaping Characters in replaceAll()
The replaceAll() method can take a regex or a typical string as the first argument. It is because a typical string in itself is a regex.
In regex, there are characters that have special meaning. These metacharacters are:
\ ^ $ . | ? * + {} [] ()
If you need to match substring containing these metacharacters, you can either escape these characters using \ or use the replace() method.
As you can see, when we use the replace() method, we do not need to escape metacharacters. To learn more, visit: Java String replace()
If you need to replace only the first occurrence of the matching substring, use the Java String replaceFirst() method.