QStringList::indexOf(QRegularExpression) don't work :(

[Stefanoxjx]

Hi, I've a problem searching a part of string in QStringList.
I've this QStringList:

QStringList *Choices = new QStringList;

    Choices->append("Languages|1|Italian");
    Choices->append("Languages|2|English");
    Choices->append("Languages|3|Spanish");
    Choices->append("Languages|4|Japanese");
    Choices->append("City|0|New York");
    Choices->append("City|1|Toronto");
    Choices->append("City|2|Rome");
    Choices->append("Color|2|Red");
    Choices->append("Color|1|Bronwn");
    Choices->append("Color|5|Black");
    Choices->append("Name|2|Stefano");
    Choices->append("Name|2|John");
    Choices->append("Name|2|Jack");

and I must to search first occurence of an initial part of string.
To obtain this result, I use this code:

int16_t idx = int16_t(slChoices->indexOf(QRegularExpression("^Color")));

but result is always -1 :(
I don't understand where I'm wrong.
If I test my regular expression here: https://www.debuggex.com/ it work fine.

Can you help me?
Thanks.

Stefano

[Christian Ehrlicher]

See the documentation: Returns the index position of the first exact match.

btw: There is no need to create a QStringList on the heap.

[mrjj]

Hi
Are you looking for Color in the beginning of the string ?
I was wondering if you can use
https://doc.qt.io/qt-5/qstring.html#startsWith

[KroMignon]

@Stefanoxjx said in QStringList::indexOf(QRegularExpression) don't work :(:

To obtain this result, I use this code:
int16_t idx = int16_t(slChoices->indexOf(QRegularExpression("^Color")));

As @Christian-Ehrlicher has written, you need exact match for QStringList::indexOf(), so you have to change you regex to:

int16_t idx = int16_t(slChoices->indexOf(QRegularExpression("^Color.*")));

[JonB]

@KroMignon
In which case, to confirm my understanding of https://doc.qt.io/qt-5/qstringlist.html#indexOf-4 wording which I don't find very clear, the ^ is redundant and QRegularExpression("Color.*") would match just as well? The match is against each string in the string list individually, and the regular expression is treated as though it were anchored with ^...$?

[KroMignon]

@JonB said in QStringList::indexOf(QRegularExpression) don't work :(:

The match is against each string in the string list individually, and the regular expression is treated as though it were anchored with ^...$?

Yes, this is the way QStringList::indexOf(onst QRegularExpression &re, int from = 0) is working.

[Stefanoxjx]

@KroMignon : Many thanks, it works fine :)
obviously many thanks also to all the others who answered me :)