Update clipboard Qt-bindings for flexiblity and Python3 compatibility

pandas/io/clipboard/__init__.py

@@ -18,7 +18,8 @@
 On Linux, install xclip or xsel via package manager. For example, in Debian:
 sudo apt-get install xclip
 
-Otherwise on Linux, you will need the gtk or PyQt4 modules installed.
+Otherwise on Linux, you will need the gtk or qtpy modules installed.
+qtpy also requires a python-qt-bindings module: PyQt4, PyQt5, PySide, PySide2
 
 gtk and PyQt4 modules are not available for Python 3,
 and this module does not work with PyGObject yet.
@@ -34,9 +35,9 @@
                          init_klipper_clipboard, init_no_clipboard)
 from .windows import init_windows_clipboard
 
-# `import PyQt4` sys.exit()s if DISPLAY is not in the environment.
+# `import qtpy` sys.exit()s if DISPLAY is not in the environment.
 # Thus, we need to detect the presence of $DISPLAY manually
-# and not load PyQt4 if it is absent.
+# and not load qtpy if it is absent.
 HAS_DISPLAY = os.getenv("DISPLAY", False)
 CHECK_CMD = "where" if platform.system() == "Windows" else "which"
 
@@ -68,8 +69,8 @@ def determine_clipboard():
             return init_gtk_clipboard()
 
         try:
-            # Check if PyQt4 is installed
-            import PyQt4  # noqa
+            # Check if qtpy is installed
+            import qtpy  # noqa
         except ImportError:
             pass
         else:

pandas/io/clipboard/clipboards.py

@@ -46,7 +46,7 @@ def paste_gtk():
 
 def init_qt_clipboard():
     # $DISPLAY should exist
-    from PyQt4.QtGui import QApplication
+    from qtpy.QtWidgets import QApplication
 
     # use the global instance if it exists
     app = QApplication.instance() or QApplication([])