Cannot start qtconsole on Ubuntu 15.04 for either Python 2 or Python 3. (Lack of PyQt5.)

[masasin]

I am on Ubuntu 15.04, using Python 3.5.1 as Python 3. I have installed PyQt5 using sudo apt-get install python3-pyqt5, but it didn't work. I also tried installing it from source.

After installing from source, I was able to access PyQt5 from ipython itself.

This is the output of python3 -c "import IPython; print(IPython.sys_info())"

python3 -c "import IPython; print(IPython.sys_info())" 
{'commit_hash': '8ff8693',
 'commit_source': 'installation',
 'default_encoding': 'UTF-8',
 'ipython_path': '/usr/local/lib/python3.5/dist-packages/IPython',
 'ipython_version': '4.0.3',
 'os_name': 'posix',
 'platform': 'Linux-3.19.0-42-generic-x86_64-with-Ubuntu-15.04-vivid',
 'sys_executable': '/usr/bin/python3',
 'sys_platform': 'linux',
 'sys_version': '3.5.1 (default, Dec 18 2015, 16:31:51) \n[GCC 4.9.2]'}

Here is the full traceback:

Traceback (most recent call last):
  File "/usr/local/bin/ipython3", line 11, in <module>
    sys.exit(start_ipython())
  File "/usr/local/lib/python3.5/dist-packages/IPython/__init__.py", line 119, in start_ipython
    return launch_new_instance(argv=argv, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 588, in launch_instance
    app.initialize(argv)
  File "<decorator-gen-111>", line 2, in initialize
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/IPython/terminal/ipapp.py", line 305, in initialize
    super(TerminalIPythonApp, self).initialize(argv)
  File "<decorator-gen-7>", line 2, in initialize
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/IPython/core/application.py", line 386, in initialize
    self.parse_command_line(argv)
  File "/usr/local/lib/python3.5/dist-packages/IPython/terminal/ipapp.py", line 300, in parse_command_line
    return super(TerminalIPythonApp, self).parse_command_line(argv)
  File "<decorator-gen-4>", line 2, in parse_command_line
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 485, in parse_command_line
    return self.initialize_subcommand(subc, subargv)
  File "<decorator-gen-3>", line 2, in initialize_subcommand
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 416, in initialize_subcommand
    subapp = import_item(subapp)
  File "/usr/local/lib/python3.5/dist-packages/ipython_genutils/importstring.py", line 31, in import_item
    module = __import__(package, fromlist=[obj])
  File "/usr/local/lib/python3.5/dist-packages/qtconsole/qtconsoleapp.py", line 60, in <module>
    from qtconsole.qt import QtCore, QtGui
  File "/usr/local/lib/python3.5/dist-packages/qtconsole/qt.py", line 23, in <module>
    QtCore, QtGui, QtSvg, QT_API = load_qt(api_opts)
  File "/usr/local/lib/python3.5/dist-packages/qtconsole/qt_loaders.py", line 304, in load_qt
    api_options))
ImportError: 
    Could not load requested Qt binding. Please ensure that
    PyQt4 >= 4.7, PyQt5 or PySide >= 1.0.3 is available,
    and only one is imported per session.

    Currently-imported Qt library:   None
    PyQt4 installed:                 False
    PyQt5 installed:                 False
    PySide >= 1.0.3 installed:       False
    Tried to load:                   ['pyqt5', 'pyside', 'pyqt']

Python 2 has a similar issue. This is the output of python -c "import IPython; print(IPython.sys_info())":

{'commit_hash': u'f534027',
 'commit_source': 'installation',
 'default_encoding': 'UTF-8',
 'ipython_path': '/usr/local/lib/python2.7/dist-packages/IPython',
 'ipython_version': '4.0.0',
 'os_name': 'posix',
 'platform': 'Linux-3.19.0-42-generic-x86_64-with-Ubuntu-15.04-vivid',
 'sys_executable': '/usr/bin/python',
 'sys_platform': 'linux2',
 'sys_version': '2.7.9 (default, Apr  2 2015, 15:33:21) \n[GCC 4.9.2]'}

and the traceback:

Traceback (most recent call last):
  File "/usr/local/bin/ipython", line 11, in <module>
    sys.exit(start_ipython())
  File "/usr/local/lib/python3.5/dist-packages/IPython/__init__.py", line 119, in start_ipython
    return launch_new_instance(argv=argv, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 588, in launch_instance
    app.initialize(argv)
  File "<decorator-gen-111>", line 2, in initialize
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/IPython/terminal/ipapp.py", line 305, in initialize
    super(TerminalIPythonApp, self).initialize(argv)
  File "<decorator-gen-7>", line 2, in initialize
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/IPython/core/application.py", line 386, in initialize
    self.parse_command_line(argv)
  File "/usr/local/lib/python3.5/dist-packages/IPython/terminal/ipapp.py", line 300, in parse_command_line
    return super(TerminalIPythonApp, self).parse_command_line(argv)
  File "<decorator-gen-4>", line 2, in parse_command_line
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 485, in parse_command_line
    return self.initialize_subcommand(subc, subargv)
  File "<decorator-gen-3>", line 2, in initialize_subcommand
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 74, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/traitlets/config/application.py", line 416, in initialize_subcommand
    subapp = import_item(subapp)
  File "/usr/local/lib/python3.5/dist-packages/ipython_genutils/importstring.py", line 31, in import_item
    module = __import__(package, fromlist=[obj])
  File "/usr/local/lib/python3.5/dist-packages/qtconsole/qtconsoleapp.py", line 60, in <module>
    from qtconsole.qt import QtCore, QtGui
  File "/usr/local/lib/python3.5/dist-packages/qtconsole/qt.py", line 23, in <module>
    QtCore, QtGui, QtSvg, QT_API = load_qt(api_opts)
  File "/usr/local/lib/python3.5/dist-packages/qtconsole/qt_loaders.py", line 304, in load_qt
    api_options))
ImportError: 
    Could not load requested Qt binding. Please ensure that
    PyQt4 >= 4.7, PyQt5 or PySide >= 1.0.3 is available,
    and only one is imported per session.

    Currently-imported Qt library:   None
    PyQt4 installed:                 False
    PyQt5 installed:                 False
    PySide >= 1.0.3 installed:       False
    Tried to load:                   ['pyqt5', 'pyside', 'pyqt']

PyQt5 does not work in Python 2 at all, even though python-pyqt5 is also installed.

If this is not the right place for it, please let me know.

[ccordoba12]

I have two comments:

1. From your first traceback, I can read

   /usr/local/lib/python3.5/...
   

   This means you installed your own version of Python in /usr/local. That's why packages installed with apt-get are not detected. They are installed for your system version (present in /usr/lib), not for your local one.

   So, if you want to use PyQt5 with your local Python version, you need to compile and install PyQt5 for that version.

2. Your second traceback is obviously wrong. You claim it comes from Python 2, but it only has lines that start with

   /usr/local/lib/python3.5/
   

[takluyver]

Also, note that the Qt console requires the QtSvg module - if you don't have that, it will show the Qt binding as not available. A better error message is coming in the next version.