Java split() checking if index equals a value

Question

I have a function which gets passed in a string. From that I split the string with

String[] info = s.split("\\s+");

I then want to see if the first index is a plus sign (+). If i enter in a string: + other stuff it claims that + != +

System.out.println("Check if "+ info[0]+ " = +");
if(info[0]=="+") {
    System.out.println("yes");
} else
    System.out.println("no");

This is the output i get:

Interp> + 
Check if + = + 
no

anyone know why this is?

possible duplicate of [How do I compare strings in Java?](http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — assylias, Mar 26 '13 at 22:45

score 4 · Answer 1 · answered Mar 26 '13 at 22:44

4

It should be:

if(info.length > 0 && "+".equals(info[0])) {

answered Mar 26 '13 at 22:44

jdb

4,419
21
21

score 3 · Accepted Answer · answered Mar 26 '13 at 22:44

3

When comparing Strings, always use String.equals(String str). == will compare strings for equal memory identity, String.equals() will compare for the same content.

if(info[0].equals("+")) { do stuff.. }

answered Mar 26 '13 at 22:44

Timr

1,012
1
14
29

GameDroids · Answer 3 · 2013-03-26T22:49:21.540

For comparing two Strings you should always use myString.equals(otherstring); In your case this could be

if(info[0].equalsIgnoreCase("+") {
    System.out.println("yes");
} else
    System.out.println("no");
}

These are the possibilities for Strings:

string1.equals(string2) -> returns boolean
string1.equalsIgnoreCase(string2) -> returns boolean
string1.compareTo(string2) -> returns -1 if string1 comes alphabetically before string2, 0 if both strings are equal, +1 if string2 comes alphabetically before string1

For explanation: the == operator compares the memory reference of the two strings not the content of the strings.

Java split() checking if index equals a value

3 Answers3