Replace first three digits with 'digit' : Regular Expressions « Development « Java Tutorial

public class MainClass
{
   public static void main( String args[] )
   {
      String firstString = "This sentence ends in 5 stars *****";
      String secondString = "1, 2, 3, 4, 5, 6, 7, 8";
         
      System.out.printf( "Original String 1: %s\n", firstString );

      // replace first three digits with 'digit'     
      for ( int i = 0; i < 3; i++ )
         secondString = secondString.replaceFirst( "\\d", "digit" );

      System.out.printf( 
         "First 3 digits replaced by \"digit\" : %s\n", secondString );

   }
}

Original String 1: This sentence ends in 5 stars *****
First 3 digits replaced by "digit" : digit, digit, digit, 4, 5, 6, 7, 8

6.32.Regular Expressions
	6.32.1.	Validate the first name and last name
	6.32.2.	Validate Address
	6.32.3.	Validate city and state
	6.32.4.	Validate Zip
	6.32.5.	Validate Phone
	6.32.6.	Replace '*' with '^'
	6.32.7.	Replace one string with another string
	6.32.8.	Replace all words with another string
	6.32.9.	Replace first three digits with 'digit'
	6.32.10.	Split string with comma
	6.32.11.	Pattern match: J.*\\d[0-35-9]-\\d\\d-\\d\\d