Using HashMap over QMap
metzpinguin at gmail.com
Thu Jul 9 18:22:13 BST 2020
A QHashMap brings a speed advantage for a large number of entries, because
access is constant time. A QMap can be faster with a few, say up to 200
entries. With Qt4 there were sometimes problems if the key was a string in a
QHashMap, which was not unique when converted to a hash. That should no longer
occur with Qt5. So, many thousands of entries with a lot of access ->
QHashMap. Keep in mind that the keys of a QMap are sorted automatically.
Am Donnerstag, 9. Juli 2020, 15:24:31 CEST schrieb Kartik Ramesh:
> Hi all,
> I was working on categorizing Face Suggestions by Suggested Name. This
> would lead to a grouping of similar faces, which would be particularly
> helpful in the Unconfirmed Tag View.
> To do the categorization, I have been able to implement methods to obtain a
> Map of Face Regions -> Suggested Names for each Image. This would have
> multiple elements if an image has multiple faces. I have committed the
> implementation already.
> Since, I don't have any reason for my keys to be sorted, I was wondering if
> I should use a HashMap instead of a QMap? I have currently used a QMap
> because all methods related to Faces use it.
> Thanks in advance
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