Compare CharSequence with String.valueOf

Question

I have following code:

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        CharSequence cs = "5.00";
        double danswer = 5.0000;
        DecimalFormat df = new DecimalFormat("#.00");

        if(cs.toString() == String.valueOf(df.format(danswer)))
        {
            System.out.println("person");   
        }
        else
        {
            System.out.println("False");    
        }
    }
}

Why am i not able to compare in this case? As both are string values? How can i compare the values in this case?

Don't use `==` to compare strings. There are numerous questions on this site that will explain the correct way to do it. — Dawood ibn Kareem, Mar 23 '14 at 20:32
@Kon - Thanks! .equals work. I tried googling it but did not see the link above. — NoviceMe, Mar 23 '14 at 20:34

dashhund · Accepted Answer · 2014-03-23T23:07:10.113

1

I would only take a small search to find the answer for this, as it has already been given hundreds of times. But for those die hards who can't use a search function:

You can't use the "==" to compare Strings, NEVER. Instead, you should compare them by using ".equals()"

in your example:if(cs.toString().equals(String.valueOf(df.format(danswer))))

edited Mar 23 '14 at 23:07

answered Mar 23 '14 at 20:39

dashhund

322
3
17

1

maybe not never. for intern()ed constants (either with intern() of with your own pool), you can safely use ==, but that's a very specific case. – Teovald Feb 04 '15 at 18:23

score 0 · Answer 2 · answered Mar 23 '14 at 20:43

0

use equal method. String a="abc"; if(a.equal("abc"))

use that in your code

answered Mar 23 '14 at 20:43

nik

210
3
13

score 0 · Answer 3 · answered Mar 23 '14 at 20:57

In this case you want to compare 2 strings but operator "==" is operator that compare boolean and numeric type. When you want to compare strings always use .equals() method because strings need to compare char by char and .equals() do that for you. Every string has .equals() function

class Ideone
        {
public static void main (String[] args) throws java.lang.Exception
{

    CharSequence cs = "5.00";
    double danswer = 5.0000;
    DecimalFormat df = new DecimalFormat("#.00");

    if(cs.toString().equals(String.valueOf(df.format(danswer))))
    {
        System.out.println("person");   
    }
    else
    {
        System.out.println("False");    
    }
}

} This can work fine!

Compare CharSequence with String.valueOf

3 Answers3