How to Compare two Qstrings?

Question

I have to compare two Qstrings in qt,

say,

Qstring str1="1005",str2="1006";

I have tried using ,

if(str1==str2){
   return true;
}

&

if(str1.compare(str2)==0)
{
    return true;
}

still both methods goes inside if condition & returns true.

Yes, I have checked the same in debugging mode and surprisingly it was going inside the if condition. — krohit, Oct 09 '13 at 06:37
How about an SSCCE? In particular, show what your function is supposed to return when the strings aren't equal. — Rob Kennedy, Oct 09 '13 at 06:57
You actually mean `QString`, right? Please try to provide an [SSCCE](http://sscce.org/) we could just paste into a file and build. — Angew is no longer proud of SO, Oct 09 '13 at 07:13
Do you want to compare for equality? If so, what is the problem with `==`? — juanchopanza, Oct 09 '13 at 07:17
I couldn't reproduce it. Are you sure you didn't modify any of them in between declaring and comparing? And is `Qstring` is just a typo or you have a custom type named exactly `Qstring`? — Mousa, Oct 09 '13 at 07:21
This question is about a problem caused by a stale build. The answer won't help anyone else, since the problem is *not* with the code. It's off topic. — Kuba hasn't forgotten Monica, Oct 09 '13 at 10:50

score 52 · Answer 1 · answered Oct 09 '13 at 06:41

52

You can use :

int x = QString::compare(str1, str2, Qt::CaseInsensitive);  // if strings are equal x should return 0

answered Oct 09 '13 at 06:41

mcelik

1,073
2
12
22

13

Although the question asks how to compare strings, that's not *really* what it's asking since the question already demonstrates two ways of comparing strings, including the one suggested in this answer. The question means to ask why the comparisons appear to evaluate to unexpected results. Case sensitivity isn't involved in the example given. – Rob Kennedy Oct 09 '13 at 06:54
Third parameter can be changed according to how you want to compare them. I just gave an example of comparing strings. – mcelik Oct 09 '13 at 06:59
1

But the OP already has two examples of how to compare strings in his question, both of which are correct. So that is not the problem. – Benjamin Lindley Oct 09 '13 at 07:07
btw ur code is invalid because QString::compare isn't static, so u cannot use it as u wrote, it should be: int x = str1.compare(str2); – borune Jun 18 '19 at 07:23

score 17 · Answer 2 · edited Aug 19 '21 at 03:44

17

The code below works fine for me.

int main(int argv, char **args)
 {
    QString str1="1005",str2="1006";
    if(str1 == str2)
        qDebug()<<"This should not print";
    qDebug()<<"Everything Ok";

}

Output:

Everything Ok

The == operator is overloaded for QStrings, as documented here.

I don't know why your code is not working. Recheck other parts of your code.

edited Aug 19 '21 at 03:44

markasoftware

12,292
8
41
69

answered Oct 09 '13 at 07:15

Barath Ravikumar

5,658
3
23
39

score 0 · Accepted Answer · answered Oct 09 '13 at 07:28

0

It worked after Rebuilding the Project , I think this is the problem with QT CREATOR

answered Oct 09 '13 at 07:28

krohit

792
1
7
26

8

This doesn't answer how to compare two QT strings. It seemly shows that you had some temporary environment problems. – Maxim Kornilov Dec 08 '14 at 10:11
18

@Maxim It doesnt mean that u'll downvote.I have posted here because I was not able to figure out the weird behavior of Qt. But if it got solved by fixing some environment related issue then it is my responsibility to let people know that it was my fault & close this thread. – krohit Dec 09 '14 at 11:38
@Maxim is correct. This answer is not useful. Hence the downvotes. – Laszlo Jan 07 '20 at 02:31
1

Not an answer, but might have been included as an update to the question – AlainD Jul 13 '20 at 14:55

How to Compare two Qstrings?

3 Answers3