QSortFilterProxyModel

The QSortFilterProxyModel class provides support for sorting and filtering data passed between another model and a view. More

Inheritance diagram of PySide6.QtCore.QSortFilterProxyModel

Synopsis

Functions

Virtual functions

Detailed Description

QSortFilterProxyModel can be used for sorting items, filtering out items, or both. The model transforms the structure of a source model by mapping the model indexes it supplies to new indexes, corresponding to different locations, for views to use. This approach allows a given source model to be restructured as far as views are concerned without requiring any transformations on the underlying data, and without duplicating the data in memory.

Let’s assume that we want to sort and filter the items provided by a custom model. The code to set up the model and the view, without sorting and filtering, would look like this:

treeView = QTreeView()

To add sorting and filtering support to MyItemModel, we need to create a QSortFilterProxyModel , call setSourceModel() with the MyItemModel as argument, and install the QSortFilterProxyModel on the view:

treeView = QTreeView()        MyItemModel *sourceModel = new MyItemModel(this);
QSortFilterProxyModel *proxyModel = new QSortFilterProxyModel(this);

proxyModel->setSourceModel(sourceModel);
treeView->setModel(proxyModel);

At this point, neither sorting nor filtering is enabled; the original data is displayed in the view. Any changes made through the QSortFilterProxyModel are applied to the original model.

The QSortFilterProxyModel acts as a wrapper for the original model. If you need to convert source QModelIndex es to sorted/filtered model indexes or vice versa, use mapToSource() , mapFromSource() , mapSelectionToSource() , and mapSelectionFromSource() .

Note

By default, the model dynamically re-sorts and re-filters data whenever the original model changes. This behavior can be changed by setting the dynamicSortFilter property.

The Basic Sort/Filter Model and Custom Sort/Filter Model examples illustrate how to use QSortFilterProxyModel to perform basic sorting and filtering and how to subclass it to implement custom behavior.

Sorting

QTableView and QTreeView have a sortingEnabled property that controls whether the user can sort the view by clicking the view’s horizontal header. For example:

treeView->setSortingEnabled(true);

When this feature is on (the default is off), clicking on a header section sorts the items according to that column. By clicking repeatedly, the user can alternate between ascending and descending order.

../../_images/qsortfilterproxymodel-sorting.png

Behind the scene, the view calls the sort() virtual function on the model to reorder the data in the model. To make your data sortable, you can either implement sort() in your model, or use a QSortFilterProxyModel to wrap your model – QSortFilterProxyModel provides a generic sort() reimplementation that operates on the sortRole() ( DisplayRole by default) of the items and that understands several data types, including int, QString , and QDateTime . For hierarchical models, sorting is applied recursively to all child items. String comparisons are case sensitive by default; this can be changed by setting the sortCaseSensitivity property.

Custom sorting behavior is achieved by subclassing QSortFilterProxyModel and reimplementing lessThan() , which is used to compare items. For example:

bool MySortFilterProxyModel::lessThan(const QModelIndex &left,
                                      const QModelIndex &right) const
{
    QVariant leftData = sourceModel()->data(left);
    QVariant rightData = sourceModel()->data(right);



    if (leftData.userType() == QMetaType::QDateTime) {
        return leftData.toDateTime() < rightData.toDateTime();
    } else {
        static const QRegularExpression emailPattern("[\\w\\.]*@[\\w\\.]*");

        QString leftString = leftData.toString();
        if (left.column() == 1) {
            const QRegularExpressionMatch match = emailPattern.match(leftString);
            if (match.hasMatch())
                leftString = match.captured(0);
        }
        QString rightString = rightData.toString();
        if (right.column() == 1) {
            const QRegularExpressionMatch match = emailPattern.match(rightString);
            if (match.hasMatch())
                rightString = match.captured(0);
        }

        return QString::localeAwareCompare(leftString, rightString) < 0;
    }
}

(This code snippet comes from the Custom Sort/Filter Model example.)

An alternative approach to sorting is to disable sorting on the view and to impose a certain order to the user. This is done by explicitly calling sort() with the desired column and order as arguments on the QSortFilterProxyModel (or on the original model if it implements sort() ). For example:

proxyModel->sort(2, Qt::AscendingOrder);

QSortFilterProxyModel can be sorted by column -1, in which case it returns to the sort order of the underlying source model.

Filtering

In addition to sorting, QSortFilterProxyModel can be used to hide items that do not match a certain filter. The filter is specified using a QRegularExpression object and is applied to the filterRole() ( DisplayRole by default) of each item, for a given column. The QRegularExpression object can be used to match a regular expression, a wildcard pattern, or a fixed string. For example:

proxyModel.setFilterRegularExpression(QRegularExpression("\.png", QRegularExpression.CaseInsensitiveOption))
proxyModel.setFilterKeyColumn(1)

For hierarchical models, the filter is applied recursively to all children. If a parent item doesn’t match the filter, none of its children will be shown.

A common use case is to let the user specify the filter regular expression, wildcard pattern, or fixed string in a QLineEdit and to connect the textChanged() signal to setFilterRegularExpression() , setFilterWildcard() , or setFilterFixedString() to reapply the filter.

Custom filtering behavior can be achieved by reimplementing the filterAcceptsRow() and filterAcceptsColumn() functions. For example (from the Custom Sort/Filter Model example), the following implementation ignores the filterKeyColumn property and performs filtering on columns 0, 1, and 2:

bool MySortFilterProxyModel::filterAcceptsRow(int sourceRow,
                                              const QModelIndex &sourceParent) const
{
    QModelIndex index0 = sourceModel()->index(sourceRow, 0, sourceParent);
    QModelIndex index1 = sourceModel()->index(sourceRow, 1, sourceParent);
    QModelIndex index2 = sourceModel()->index(sourceRow, 2, sourceParent);

    return (sourceModel()->data(index0).toString().contains(filterRegularExpression())
            || sourceModel()->data(index1).toString().contains(filterRegularExpression()))
            && dateInRange(sourceModel()->data(index2).toDate());
}

(This code snippet comes from the Custom Sort/Filter Model example.)

If you are working with large amounts of filtering and have to invoke invalidateFilter() repeatedly, using beginResetModel() / endResetModel() may be more efficient, depending on the implementation of your model. However, beginResetModel() / endResetModel() returns the proxy model to its original state, losing selection information, and will cause the proxy model to be repopulated.

Subclassing

Since QAbstractProxyModel and its subclasses are derived from QAbstractItemModel , much of the same advice about subclassing normal models also applies to proxy models. In addition, it is worth noting that many of the default implementations of functions in this class are written so that they call the equivalent functions in the relevant source model. This simple proxying mechanism may need to be overridden for source models with more complex behavior; for example, if the source model provides a custom hasChildren() implementation, you should also provide one in the proxy model.

Note

Some general guidelines for subclassing models are available in the Model Subclassing Reference .

class PySide6.QtCore.QSortFilterProxyModel([parent=None])
Parameters

parentPySide6.QtCore.QObject

Constructs a sorting filter model with the given parent.

PySide6.QtCore.QSortFilterProxyModel.autoAcceptChildRows()
Return type

bool

PySide6.QtCore.QSortFilterProxyModel.autoAcceptChildRowsChanged(autoAcceptChildRows)
Parameters

autoAcceptChildRows – bool

This signals is emitted when the value of the autoAcceptChildRows property is changed.

PySide6.QtCore.QSortFilterProxyModel.dynamicSortFilter()
Return type

bool

PySide6.QtCore.QSortFilterProxyModel.dynamicSortFilterChanged(dynamicSortFilter)
Parameters

dynamicSortFilter – bool

PySide6.QtCore.QSortFilterProxyModel.filterAcceptsColumn(source_column, source_parent)
Parameters
Return type

bool

Returns true if the item in the column indicated by the given source_column and source_parent should be included in the model; otherwise returns false.

Note

The default implementation always returns true. You must reimplement this method to get the described behavior.

PySide6.QtCore.QSortFilterProxyModel.filterAcceptsRow(source_row, source_parent)
Parameters
Return type

bool

Returns true if the item in the row indicated by the given source_row and source_parent should be included in the model; otherwise returns false.

The default implementation returns true if the value held by the relevant item matches the filter string, wildcard string or regular expression.

Note

By default, the DisplayRole is used to determine if the row should be accepted or not. This can be changed by setting the filterRole property.

PySide6.QtCore.QSortFilterProxyModel.filterCaseSensitivity()
Return type

CaseSensitivity

PySide6.QtCore.QSortFilterProxyModel.filterCaseSensitivityChanged(filterCaseSensitivity)
Parameters

filterCaseSensitivityCaseSensitivity

This signal is emitted when the case sensitivity of the filter changes to filterCaseSensitivity.

PySide6.QtCore.QSortFilterProxyModel.filterKeyColumn()
Return type

int

PySide6.QtCore.QSortFilterProxyModel.filterRegularExpression()
Return type

PySide6.QtCore.QRegularExpression

PySide6.QtCore.QSortFilterProxyModel.filterRole()
Return type

int

See also

setFilterRole()

PySide6.QtCore.QSortFilterProxyModel.filterRoleChanged(filterRole)
Parameters

filterRole – int

This signal is emitted when the filter role changes to filterRole.

PySide6.QtCore.QSortFilterProxyModel.invalidate()

Invalidates the current sorting and filtering.

PySide6.QtCore.QSortFilterProxyModel.invalidateColumnsFilter()

Invalidates the current filtering for the columns.

This function should be called if you are implementing custom filtering (by filterAcceptsColumn() ), and your filter parameters have changed. This differs from invalidateFilter() in that it will not invoke filterAcceptsRow() , but only filterAcceptsColumn() . You can use this instead of invalidateFilter() if you want to hide or show a column where the rows don’t change.

PySide6.QtCore.QSortFilterProxyModel.invalidateFilter()

Invalidates the current filtering.

This function should be called if you are implementing custom filtering (e.g. filterAcceptsRow() ), and your filter parameters have changed.

PySide6.QtCore.QSortFilterProxyModel.invalidateRowsFilter()

Invalidates the current filtering for the rows.

This function should be called if you are implementing custom filtering (by filterAcceptsRow() ), and your filter parameters have changed. This differs from invalidateFilter() in that it will not invoke filterAcceptsColumn() , but only filterAcceptsRow() . You can use this instead of invalidateFilter() if you want to hide or show a row where the columns don’t change.

PySide6.QtCore.QSortFilterProxyModel.isRecursiveFilteringEnabled()
Return type

bool

PySide6.QtCore.QSortFilterProxyModel.isSortLocaleAware()
Return type

bool

PySide6.QtCore.QSortFilterProxyModel.lessThan(source_left, source_right)
Parameters
Return type

bool

Returns true if the value of the item referred to by the given index source_left is less than the value of the item referred to by the given index source_right, otherwise returns false.

This function is used as the < operator when sorting, and handles the following QVariant types:

  • Int

  • UInt

  • LongLong

  • ULongLong

  • Float

  • Double

  • QChar

  • QDate

  • QTime

  • QDateTime

  • QString

Any other type will be converted to a QString using toString() .

Comparison of QString s is case sensitive by default; this can be changed using the sortCaseSensitivity property.

By default, the DisplayRole associated with the QModelIndex es is used for comparisons. This can be changed by setting the sortRole property.

Note

The indices passed in correspond to the source model.

PySide6.QtCore.QSortFilterProxyModel.recursiveFilteringEnabledChanged(recursiveFilteringEnabled)
Parameters

recursiveFilteringEnabled – bool

This signal is emitted when the recursive filter setting is changed to recursiveFilteringEnabled.

PySide6.QtCore.QSortFilterProxyModel.setAutoAcceptChildRows(accept)
Parameters

accept – bool

PySide6.QtCore.QSortFilterProxyModel.setDynamicSortFilter(enable)
Parameters

enable – bool

PySide6.QtCore.QSortFilterProxyModel.setFilterCaseSensitivity(cs)
Parameters

csCaseSensitivity

PySide6.QtCore.QSortFilterProxyModel.setFilterFixedString(pattern)
Parameters

pattern – str

Sets the fixed string used to filter the contents of the source model to the given pattern.

PySide6.QtCore.QSortFilterProxyModel.setFilterKeyColumn(column)
Parameters

column – int

PySide6.QtCore.QSortFilterProxyModel.setFilterRegularExpression(regularExpression)
Parameters

regularExpressionPySide6.QtCore.QRegularExpression

PySide6.QtCore.QSortFilterProxyModel.setFilterRegularExpression(pattern)
Parameters

pattern – str

PySide6.QtCore.QSortFilterProxyModel.setFilterRole(role)
Parameters

role – int

See also

filterRole()

PySide6.QtCore.QSortFilterProxyModel.setFilterWildcard(pattern)
Parameters

pattern – str

Sets the wildcard expression used to filter the contents of the source model to the given pattern.

PySide6.QtCore.QSortFilterProxyModel.setRecursiveFilteringEnabled(recursive)
Parameters

recursive – bool

PySide6.QtCore.QSortFilterProxyModel.setSortCaseSensitivity(cs)
Parameters

csCaseSensitivity

PySide6.QtCore.QSortFilterProxyModel.setSortLocaleAware(on)
Parameters

on – bool

PySide6.QtCore.QSortFilterProxyModel.setSortRole(role)
Parameters

role – int

See also

sortRole()

PySide6.QtCore.QSortFilterProxyModel.sortCaseSensitivity()
Return type

CaseSensitivity

PySide6.QtCore.QSortFilterProxyModel.sortCaseSensitivityChanged(sortCaseSensitivity)
Parameters

sortCaseSensitivityCaseSensitivity

This signal is emitted when the case sensitivity for sorting changes to sortCaseSensitivity.

PySide6.QtCore.QSortFilterProxyModel.sortColumn()
Return type

int

the column currently used for sorting

This returns the most recently used sort column.

PySide6.QtCore.QSortFilterProxyModel.sortLocaleAwareChanged(sortLocaleAware)
Parameters

sortLocaleAware – bool

This signal is emitted when the locale aware setting changes to sortLocaleAware.

PySide6.QtCore.QSortFilterProxyModel.sortOrder()
Return type

SortOrder

the order currently used for sorting

This returns the most recently used sort order.

PySide6.QtCore.QSortFilterProxyModel.sortRole()
Return type

int

See also

setSortRole()

PySide6.QtCore.QSortFilterProxyModel.sortRoleChanged(sortRole)
Parameters

sortRole – int

This signal is emitted when the sort role changes to sortRole.