String replace function not replacing characters correctly - Java

Question

I am trying to replace a specific character '8' with a '2' in a string. I think I have everything set up correctly and when I look online for examples, this looks like it should. When I print the string though, it is just as I entered it. To run it, test it with "80802" or some similar input. Thanks!

import java.util.Scanner; class PhoneNumber { public static void main(String[] args) { String number = null; Scanner scan = new Scanner(System.in); // Prompt the user for a telephone number System.out.print("Enter your telephone number: "); // Input the user's name number = scan.nextLine(); // Replace the relevant letters with numbers number.replace('8', '2'); System.out.println("Your number is: " + number ); } }

Bohemian · Accepted Answer · 2011-07-17 05:37:08Z

6

A common mistake... You want:

 number = number.replace('8', '2');

String.replace() doesn't change the String, because Strings are immutable (they can not be changed). Instead, such methods return a new String with the calculated value.

answered Jul 17, 2011 at 5:37

Bohemian♦

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2 Comments

Thaddius Naups Over a year ago

Ahh. So that simply creates a new string with 8's as 2's and reassigns it to number?

Thaddius Naups Over a year ago

Works perfectly and makes great sense! Thank you so much and I am pleased to know it is a common mistake =x

Ray Toal · Accepted Answer · 2011-07-17 05:36:35Z

2

number.replace() returns a new string. It does not change `number'.

answered Jul 17, 2011 at 5:36

Ray Toal

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Comments

Martijn Courteaux · Accepted Answer · 2011-07-17 07:54:18Z

number.replace('8','2'); returns the correct string it does not modify number. To get your desired functionality you must type number = number.replace('8','2');

public static void main(String[] args) { String number = null; Scanner scan = new Scanner(System.in); // Prompt the user for a telephone number System.out.print("Enter your telephone number: "); // Input the user's name number = scan.nextLine(); // Replace the relevant letters with numbers number = number.replace('8', '2'); System.out.println("Your number is: " + number ); }

Hope this helps.

Another user answered first but it does really help! Thank you!

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