PyQt

Main components

PyQt4 contains the following Python modules.

• The QtCore module contains the core non-GUI classes, including the event loop and Qt's signal and slot mechanism. It also includes platform independent abstractions for Unicode, threads, mapped files, shared memory, regular expressions, and user and application settings.
• The QtGui module contains the majority of the GUI classes. These include a number of table, tree and list classes based on the model–view–controller design pattern. Also provided is a sophisticated 2D canvas widget capable of storing thousands of items including ordinary widgets.
• The QtNetwork module contains classes for writing UDP and TCP clients and servers. It includes classes that implement FTP and HTTP clients and support DNS lookups. Network events are integrated with the event loop making it very easy to develop networked applications.
• The QtOpenGL module contains classes that enable the use of OpenGL in rendering 3D graphics in PyQt applications.
• The QtSql module contains classes that integrate with open-source and proprietary SQL databases. It includes editable data models for database tables that can be used with GUI classes. It also includes an implementation of SQLite.
• The QtSvg module contains classes for displaying the contents of SVG files. It supports the static features of SVG 1.2 Tiny.
• The QtXml module implements SAX and DOM interfaces to Qt's XML parser.
• The QtMultimedia module implements low-level multimedia functionality. Application developers would normally use the phonon module.
• The QtDesigner module contains classes that allow Qt Designer to be extended using PyQt.
• The Qt module consolidates the classes contained in all of the modules described above into a single module. This has the advantage that you don't have to worry about which underlying module contains a particular class. It has the disadvantage that it loads the whole of the Qt framework, thereby increasing the memory footprint of an application. Whether you use this consolidated module, or the individual component modules is down to personal taste.
• The uic module implements support for handling the XML files created by Qt Designer that describe the whole or part of a graphical user interface. It includes classes that load an XML file and render it directly, and classes that generate Python code from an XML file for later execution.

PyQt5 contains the following Python modules:

• QtQml
• QtQuick
• QtCore
• QtGui
• QtPrintSupport
• QtWidgets
• QGLContext
• QGLFormat
• QGLWidget
• QtWebKit
• QtWebKitWidgets

Versions

PyQt version 4 works with both Qt 4 and Qt 5. PyQt version 5 only supports Qt version 5, and drops support for features that are deprecated in Qt 5.

Hello World example

The below code written for PyQt6 shows a small window on the screen.

<span id="mwqQ"></span><span class="linenos" data-line="1" id="mwqg"></span><span class="ch" id="mwqw">#!/usr/bin/env python3</span> <span class="linenos" data-line="2" id="mwrA"></span><span class="sd" id="mwrQ">"""</span> <span class="linenos" data-line="3" id="mwrg"></span><span class="sd" id="mwrw">Here we provide the necessary imports.</span> <span class="linenos" data-line="4" id="mwsA"></span><span class="sd" id="mwsQ">The basic GUI widgets are located in QtWidgets module.</span> <span class="linenos" data-line="5" id="mwsg"></span><span class="sd" id="mwsw">"""</span> <span class="linenos" data-line="6" id="mwtA"></span><span class="kn" id="mwtQ">import</span><span class="w" id="mwtg"> </span><span class="nn" id="mwtw">sys</span> <span class="linenos" data-line="7" id="mwuA"></span><span class="kn" id="mwuQ">from</span><span class="w" id="mwug"> </span><span class="nn" id="mwuw">PyQt6.QtWidgets</span><span class="w" id="mwvA"> </span><span class="kn" id="mwvQ">import</span> <span class="n" id="mwvg">QApplication</span><span class="p" id="mwvw">,</span> <span class="n" id="mwwA">QWidget</span> <span class="linenos" data-line="8" id="mwwQ"></span> <span class="linenos" data-line="9" id="mwwg"></span><span class="c1" id="mwww"># Every PyQt application must create an application object.</span> <span class="linenos" data-line="10" id="mwxA"></span><span class="c1" id="mwxQ"># The application object is located in the QtWidgets module.</span> <span class="linenos" data-line="11" id="mwxg"></span><span class="n" id="mwxw">app</span> <span class="o" id="mwyA">=</span> <span class="n" id="mwyQ">QApplication</span><span class="p" id="mwyg">([])</span> <span class="linenos" data-line="12" id="mwyw"></span> <span class="linenos" data-line="13" id="mwzA"></span><span class="c1" id="mwzQ"># The QWidget widget is the base class of all user interface objects in PyQt.</span> <span class="linenos" data-line="14" id="mwzg"></span><span class="c1" id="mwzw"># We provide the default constructor for QWidget. The default constructor has no parent.</span> <span class="linenos" data-line="15" id="mw0A"></span><span class="c1" id="mw0Q"># A widget with no parent is called a window.</span> <span class="linenos" data-line="16" id="mw0g"></span><span class="n" id="mw0w">root</span> <span class="o" id="mw1A">=</span> <span class="n" id="mw1Q">QWidget</span><span class="p" id="mw1g">()</span> <span class="linenos" data-line="17" id="mw1w"></span> <span class="linenos" data-line="18" id="mw2A"></span><span class="n" id="mw2Q">root</span><span class="o" id="mw2g">.</span><span class="n" id="mw2w">resize</span><span class="p" id="mw3A">(</span><span class="mi" id="mw3Q">320</span><span class="p" id="mw3g">,</span> <span class="mi" id="mw3w">240</span><span class="p" id="mw4A">)</span> <span class="c1" id="mw4Q"># The resize() method resizes the widget.</span> <span class="linenos" data-line="19" id="mw4g"></span><span class="n" id="mw4w">root</span><span class="o" id="mw5A">.</span><span class="n" id="mw5Q">setWindowTitle</span><span class="p" id="mw5g">(</span><span class="s2" id="mw5w">"Hello, World!"</span><span class="p" id="mw6A">)</span> <span class="c1" id="mw6Q"># Here we set the title for our window.</span> <span class="linenos" data-line="20" id="mw6g"></span><span class="n" id="mw6w">root</span><span class="o" id="mw7A">.</span><span class="n" id="mw7Q">show</span><span class="p" id="mw7g">()</span> <span class="c1" id="mw7w"># The show() method displays the widget on the screen.</span> <span class="linenos" data-line="21" id="mw8A"></span> <span class="linenos" data-line="22" id="mw8Q"></span><span class="n" id="mw8g">sys</span><span class="o" id="mw8w">.</span><span class="n" id="mw9A">exit</span><span class="p" id="mw9Q">(</span><span class="n" id="mw9g">app</span><span class="o" id="mw9w">.</span><span class="n" id="mw-A">exec</span><span class="p" id="mw-Q">())</span> <span class="c1" id="mw-g"># Finally, we enter the mainloop of the application.</span>

Notable applications that use PyQt

• Anki, a spaced repetition flashcard program
• Calibre, an E-book management application
• Dropbox, a file hosting service
• EarQuiz Frequencies, a free and open-source application for EQ/frequency ear training
• Electrum Bitcoin Wallet
• Eric Python IDE
• Frescobaldi, a score editor for LilyPond music files
• Kodos, a Python Regular expression Debugger
• Leo, an outliner and literate programming editor
• OpenLP, an open-source lyrics projection program
• OpenShot, a video editing program
• Orange, a data mining and visualization framework
• Puddletag, an open-source, cross-platform ID3 tag editor
• QGIS, a free software desktop Geographic Information Systems (GIS) application
• qutebrowser, a web browser with Vim-style key bindings and a minimal GUI.
• qt-recordMyDesktop, a Qt4 frontend for recordMyDesktop
• Spyder, a Python data science IDE
• TortoiseHg, a graphical interface for the Mercurial source management program (Hg)
• Veusz, a scientific plotting application
• GNS3, a network software emulator