Sort a QHash<QRgb, int> by value

[niko]

Hello,

how can i sort a QHash by the int value?
qSort doesn't work with QHash.

thanks
Niko

[jacek]

Hashes have no order. You can create a list of pairs and sort it.

[danadam]

You can't sort QHash. From docs:

When iterating over a QMap, the items are always sorted by key. With QHash, the items are arbitrarily ordered.

If you want to have elements of QHash<QRgb, int> sorted, you could copy them to QMap<int, QRgb>. In that way you'll have them sorted by int.

EDIT:
Although Jacek gave better solution

[niko]

thanks for the answers!

Hashes have no order. You can create a list of pairs and sort it.

you mean like this?

class ColorCount {
public:
  QRgb rgb;
  int count;
  operator <();
};
QList<ColorCount> colors;
...
qSort(colors);

class ColorCount {
public:
  QRgb rgb;
  int count;
  operator <();
};
QList<ColorCount> colors;
...
qSort(colors);

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i thought about that too allready, but adding values to the list looks quite difficult and expensive to me, with QHash i could do:

QHash<QRgb, int> colors;
colors[QRgb(...)]++;

QHash<QRgb, int> colors;
colors[QRgb(...)]++;

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and with the list i have to search everytime through the whole list to find the right entry.

..although i could create a temporary QHash that just stores the position of the color in the QList... i guess the would speed it up again!


thx
niko

[jacek]

although i could create a temporary QHash that just stores the position of the color in the QList

Or create that list after you have finished colour counting.

[niko]

yes, thats easier;

thx