Add more python code

Python-Examples/README.md

@@ -21,7 +21,10 @@ Various Code Snippets on different topics about Python
 
   1. [merge_sort]
      (merge_sort.py)
+3. **Color in terminal**
 
+    ![Color in terminal](terminal/color_in_terminal.png)
+
 4. Requests - Requests-futures
 
     A small example in terms of demonstrating the parallelization of

Python-Examples/mmap/shared_memory_read.py

@@ -15,13 +15,13 @@ def main():
     s = None
 
     while 1:
-        new_i = struct.unpack('i', buf[:4])
-        new_s = struct.unpack('3s', buf[4:7])
+        new_i, = struct.unpack('i', buf[:4])
+        new_s, = struct.unpack('3s', buf[4:7])
 
         if i != new_i or s != new_s:
-            print "i: {} => {}".format(i, new_i)
-            print "s: {} => {}".format(s, new_s)
-            print 'Press Ctrl-C to exit'
+            print('i: %s => %d' % (i, new_i))
+            print('s: %s => %s' % (s, new_s))
+            print('Press Ctrl-C to exit')
             i = new_i
             s = new_s
 

Python-Examples/mmap/shared_memory_write.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 import ctypes
 import mmap
 import os
@@ -9,7 +10,7 @@ def main():
     fd = os.open('/tmp/mmaptest', os.O_CREAT | os.O_TRUNC | os.O_RDWR)
 
     # Zero out the file to insure it's the right size
-    assert os.write(fd, '\x00' * mmap.PAGESIZE) == mmap.PAGESIZE
+    assert os.write(fd, bytes('\x00' * mmap.PAGESIZE,'utf8')) == mmap.PAGESIZE
 
     # Create the mmap instace with the following params:
     # fd: File descriptor which backs the mapping or -1 for anonymous mapping
@@ -30,33 +31,35 @@ def main():
     assert i.value == 11
 
     # Before we create a new value, we need to find the offset of the next free
-    # memory address within the map
+    # memory address within the mmap
     offset = struct.calcsize(i._type_)
 
     # The offset should be uninitialized ('\x00')
-    assert buf[offset] == '\x00'
+    print(buf[offset])
+    assert buf[offset] == 0
 
-    # Now create a string containing 'foo' by first creating a c_char array
-    s_type = ctypes.c_char * (len('foo'))
+    # Now ceate a string containing 'foo' by first creating a c_char array
+    s_type = ctypes.c_char * len('foo')
 
     # Now create the ctypes instance
     s = s_type.from_buffer(buf, offset)
 
     # And finally set it
-    s.raw = 'foo'
+    s.raw = bytes('foo','utf8')
 
-    print 'First 10 bytes of memory mapping: %r' % buf[:10]
-    raw_input('Now run shared_memory_read.py and press ENTER')
+    print('First 10 bytes of memory mapping: %r' % buf[:10])
+    # input('Now run b.py and press ENTER')
 
-    print
-    print 'Changing i'
+    print('Now i:', i.value)
+    print('Changing i')
     i.value *= i.value
 
-    print 'Changing s'
-    s.raw = 'bar'
+    print('Changing s')
+    s.raw = bytes('bar','utf8')
 
-    new_i = raw_input('Enter a new value for i: ')
+    new_i = input('Enter a new value for i: ')
     i.value = int(new_i)
+    print('Now i:', i.value)
 
 if __name__ == '__main__':
     main()

Python-Examples/pyqt/colorsModel.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+from  PyQt5.QtWidgets import (QWidget, QDataWidgetMapper,
+                              QLineEdit, QApplication, QGridLayout, QListView)
+from PyQt5.QtCore import Qt, QAbstractTableModel, QModelIndex
+
+
+class Window(QWidget):
+    def __init__(self, parent=None):
+        super(Window, self).__init__(parent)
+
+        # Set up the widgets.
+        self.nameEdit = QLineEdit()
+        self.nameEdit2 = QLineEdit()
+
+        # set up the layout
+        layout = QGridLayout()
+        layout.addWidget(self.nameEdit, 0, 1, 1, 1)
+        layout.addWidget(self.nameEdit2, 0, 2, 1, 1)
+        self.setLayout(layout)
+
+        self.mapper = None
+
+    def setModel(self, model):
+        # Set up the mapper.
+        self.mapper = QDataWidgetMapper(self)
+        self.mapper.setModel(model)
+        self.mapper.addMapping(self.nameEdit, 0)
+        self.mapper.addMapping(self.nameEdit2, 1)
+        self.mapper.toFirst()
+
+
+class MyModel(QAbstractTableModel):
+    def __init__(self, data, parent=None):
+        QAbstractTableModel.__init__(self, parent)
+        self.lst = data
+
+    def columnCount(self, parent=QModelIndex()):
+        return len(self.lst[0])
+
+    def rowCount(self, parent=QModelIndex()):
+        return len(self.lst)
+
+    def data(self, index, role=Qt.DisplayRole):
+        row = index.row()
+        col = index.column()
+
+        if role == Qt.EditRole:
+            return self.lst[row][col]
+        elif role == Qt.DisplayRole:
+            return self.lst[row][col]
+
+    def flags(self, index):
+        flags = super(MyModel, self).flags(index)
+
+        if index.isValid():
+            flags |= Qt.ItemIsEditable
+            flags |= Qt.ItemIsDragEnabled
+        else:
+            flags = Qt.ItemIsDropEnabled
+
+        return flags
+
+    def setData(self, index, value, role=Qt.EditRole):
+
+        if not index.isValid() or role != Qt.EditRole:
+            return False
+
+        self.lst[index.row()][index.column()] = value
+        self.dataChanged.emit(index, index)
+        return True
+
+
+if __name__ == '__main__':
+    import sys
+
+    app = QApplication(sys.argv)
+
+    myModel = MyModel([['row 1 col1', 'row 1 col2'],
+                       ['row 2 col1', 'row 2 col2'],
+                       ['row 3 col1', 'row 3 col2'],
+                       ['row 4 col1', 'row 4 col2']])
+
+    # myModel = MyModel()
+    mywindow = Window()
+    mywindow.setModel(myModel)
+
+    qlistview2 = QListView()
+    qlistview2.setModel(myModel)
+
+    mywindow.show()
+    qlistview2.show()
+
+    sys.exit(app.exec_())

Python-Examples/singleton/main.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+longqi 22/Dec/16 15:12
+Description:
+To create a singleton class, you subclass from Singleton; each subclass will have a single instance, no matter how many
+times its constructor is called. To further initialize the subclass instance, subclasses should override 'init' instead
+of __init__ - the __init__ method is called each time the constructor is called
+
+"""
+
+
+class Singleton(object):
+	def __new__(cls, *args, **kwargs):
+		it = cls.__dict__.get("__it__")
+		print('******* new *****')
+
+		# print(it)
+		# print(cls)
+		# print(cls.__dict__)
+		if it is not None:
+			return it
+		cls.__it__ = it = object.__new__(cls)
+		# it = object.__new__(cls)
+		it.init(*args, **kwargs)
+		return it
+
+	def init(self, *args, **kwargs):
+		print('init', args)
+		self.data = args
+		pass
+
+	def __init__(self, *args):
+		self.data = []
+		print('__init__')
+
+
+a = Singleton('a')
+b = Singleton('b')
+c = Singleton('c')
+
+assert a == b == c

Python-Examples/terminal/color_output.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+longqi 22/Nov/16 14:19
+Description:
+
+https://en.wikipedia.org/wiki/ANSI_escape_code
+
+ESC[ … 38;2;<r>;<g>;<b> … m Select RGB foreground color
+ESC[ … 48;2;<r>;<g>;<b> … m Select RGB background color
+
+In 256-color mode (ESC[38;5;<fgcode>m and ESC[48;5;<bgcode>m), the color-codes are the following:[citation needed]
+0x00-0x07:  standard colors (as in ESC [ 30–37 m)
+0x08-0x0F:  high intensity colors (as in ESC [ 90–97 m)
+0x10-0xE7:  6 × 6 × 6 = 216 colors: 16 + 36 × r + 6 × g + b (0 ≤ r, g, b ≤ 5)
+0xE8-0xFF:  gray scale from black to white in 24 steps
+ESC is  (ASCII decimal 27/hex 0x1B/octal 033)
+
+#################################################################
+### Please set the width of your terminal as wide as possible ###
+#################################################################
+"""
+print('\x1b[1m bold text\x1b[0m')  # bold
+
+print('\x1b[1m standard eight colors \x1b[0m')
+for color_code in range(30, 38):
+	print('\x1b[' + str(color_code) + 'm' + str(color_code) + '\x1b[0m', end='\t')
+print('\x1b[0m\n')  # reset color
+
+print('\x1b[1m high intensity colors \x1b[0m')
+for color_code in range(90, 98):
+	print('\x1b[' + str(color_code) + 'm' + str(color_code) + '\x1b[0m', end='\t')
+print('\x1b[0m\n')
+
+print('\x1b[1m 256-color, foreground \x1b[0m')
+for color_code in range(00, 256):
+	print('\x1b[38;5;' + str(color_code) + 'm' + str(color_code).zfill(3) + '\x1b[0m', end='\t')
+	if (color_code + 1) % 8 == 0:
+		print('')
+print('\x1b[0m\n')
+
+print('\x1b[1m 256-color, background \x1b[0m')
+for color_code in range(00, 256):
+	print('\x1b[48;5;' + str(color_code) + 'm' + str(color_code).zfill(3) + '\x1b[0m', end='\t')
+	if (color_code + 1) % 8 == 0:
+		print('')
+print('\x1b[0m\n')
+
+print('\x1b[1m RGB-color, foreground \x1b[0m')
+for R in range(0, 256, 32):
+	for G in range(0, 256, 32):
+		for B in range(0, 256, 32):
+			print('\x1b[38;2;' + str(R) + ';' + str(G) + ';' + str(B) + 'm' +
+						str(R).zfill(3) + '.' + str(G).zfill(3) + '.' + str(B).zfill(3) + '\x1b[0m',
+						end='\t')
+		print('')
+print('\x1b[0m\n')
+
+print('\x1b[1m RGB-color, background \x1b[0m')
+for R in range(0, 256, 32):
+	for G in range(0, 256, 32):
+		for B in range(0, 256, 32):
+			print('\x1b[48;2;' + str(R) + ';' + str(G) + ';' + str(B) + 'm' +
+						str(R).zfill(3) + '.' + str(G).zfill(3) + '.' + str(B).zfill(3) + '\x1b[0m',
+						end='\t')
+		print('')
+
+print('\x1b[0m\n')