What does the qhash class do in Qt?
The QHash class is a template class that provides a hash-table-based dictionary. QHash is one of Qt’s generic container classes. It stores (key, value) pairs and provides very fast lookup of the value associated with a key. QHash provides very similar functionality to QMap.
What does the qset class do in Qt?
The QSet class is a template class that provides a hash-table-based set. More… Note: All functions in this class are reentrant. QSet is one of Qt’s generic container classes. It stores values in an unspecified order and provides very fast lookup of the values. Internally, QSet is implemented as a QHash.
How to insert multiple values into a qhash?
To insert a (key, value) pair into the hash, we can use insert (): or use operator [] (): We can store multiple values per key by using insertMulti () instead of insert (). If we want to navigate through all the (key, value) pairs stored in a QHash, we can use an iterator.
What’s the difference between a QMap and a qhash?
The differences are: QHash provides faster lookups than QMap. When iterating over a QMap, the items are always sorted by key. With QHash, the items are arbitrarily ordered. The key type of a QMap must provide operator< ().
The QHash class is a template class that provides a hash-table-based dictionary. More… Note: All functions in this class are reentrant. The QHash class is a template class that provides a hash-table-based dictionary. QHash is one of Qt’s generic container classes.
How to remove an item from a qhash hash?
Items can be removed from the hash in several ways. One way is to call remove (); this will remove any item with the given key. Another way is to use QMutableHashIterator::remove (). In addition, you can clear the entire hash using clear (). QHash ‘s key and value data types must be assignable data types.
How does the insert iterator in qhash work?
QHash::iterator QHash::insert(const Key &key, const T &value) Inserts a new item with the key and a value of value. If there is already an item with the key, that item’s value is replaced with value. If there are multiple items with the key, the most recently inserted item’s value is replaced with value.
Is there a way to hash qvariant in Qt?
Get yourself a QByteArray + QBuffer + QDataStream to basically serialize QVariant s to the QByteArray. Then simply hash the raw bytes in the byte array. Qt already implements a qHash function for QByteArray so you are all set.