Improve Python 3 compatibility for example scripts.

examples/core/appconfig.py

@@ -30,8 +30,6 b' When the config attribute of an Application is updated, it will fire all of'
 the trait's events for all of the config=True attributes.
 """
 
-import sys
-
 from IPython.config.configurable import Configurable
 from IPython.config.application import Application
 from IPython.utils.traitlets import (
@@ -87,8 +85,8 b' class MyApp(Application):'
         self.init_bar()
     
     def start(self):
-        print "app.config:"
-        print self.config
+        print("app.config:")
+        print(self.config)
 
 
 def main():

examples/core/ipython-get-history.py

@@ -17,7 +17,6 b' to build much more flexible and powerful tools to browse and pull from the'
 history database.
 """
 import sys
-import codecs
 
 from IPython.core.history import HistoryAccessor
 
@@ -34,5 +33,5 b' dest.write("# coding: utf-8\\n")'
 hist = HistoryAccessor()
 
 for session, lineno, cell in hist.get_range(session=session_number, raw=raw):
-    # To use this in Python 3, remove the .encode() here:
-    dest.write(cell.encode('utf-8') + '\n')
+    cell = cell.encode('utf-8')  # This line is only needed on Python 2.
+    dest.write(cell + '\n')

examples/inprocess/embedded_qtconsole.py

@@ -1,3 +1,4 b''
+from __future__ import print_function
 import os
 
 from IPython.qt.console.rich_ipython_widget import RichIPythonWidget
@@ -6,7 +7,7 b' from IPython.lib import guisupport'
 
 
 def print_process_id():
-    print 'Process ID is:', os.getpid()
+    print('Process ID is:', os.getpid())
 
 
 def main():

examples/inprocess/embedded_terminal.py

@@ -1,3 +1,4 b''
+from __future__ import print_function
 import os
 
 from IPython.kernel.inprocess import InProcessKernelManager
@@ -5,7 +6,7 b' from IPython.terminal.console.interactiveshell import ZMQTerminalInteractiveShel'
 
 
 def print_process_id():
-    print 'Process ID is:', os.getpid()
+    print('Process ID is:', os.getpid())
 
 
 def main():

examples/lib/gui-qt.py

@@ -10,7 +10,6 b' In [6]: %run gui-qt.py'
 Ref: Modified from http://zetcode.com/tutorials/pyqt4/firstprograms/
 """
 
-import sys
 from PyQt4 import QtGui, QtCore
 
 class SimpleWindow(QtGui.QWidget):

examples/lib/gui-tk.py

@@ -8,7 +8,10 b' In [5]: %gui tk'
 In [6]: %run gui-tk.py
 """
 
-from Tkinter import *
+try:
+    from tkinter import *  # Python 3
+except ImportError:
+    from Tkinter import *  # Python 2
 
 class MyApp:
 

examples/lib/internal_ipkernel.py

@@ -2,7 +2,6 b''
 # Imports
 #-----------------------------------------------------------------------------
 
-import subprocess
 import sys
 
 from IPython.lib.kernel import connect_qtconsole
@@ -42,7 +41,7 b' class InternalIPKernel(object):'
 
     def print_namespace(self, evt=None):
         print("\n***Variables in User namespace***")
-        for k, v in self.namespace.iteritems():
+        for k, v in self.namespace.items():
             if k not in self._init_keys and not k.startswith('_'):
                 print('%s -> %r' % (k, v))
         sys.stdout.flush()