Easiest to Highest

Python

All rights reserved by John Yoon at Mercy College, New York, U.S.A. in 2017

PART 1: Python Element

1. Python Basics by Examples

2. Conditions and Repetitions

3. Data Manipulation

3.1 Acquiring Data

3.2 Handling Numbers

3.3 Handling Strings

4. Accessing External Sources

4.1 Accessing Files

4.2 Accessing Applications

4.3 Accessing Operating Systems

4.4 Accessing Database Servers

4.5 Accessing Networks

4.6 Accessing Webpages

5. Graphical User Interfaces

6. Python Advanced Programming

6.1 Command-line Parameters

6.2 Recursion

6.3 Multiprocessing

6.4 Multithreading

PART 2: Python Application

7. Financial Applications

8. Healthcare Applications

9. Cybersecurity Applications

a. Cyber Attack

b. Cyber Defense

10. Wireless Communication and Security

10.1 Sinusoidal Wave and FFT

10.2

11. Data Mining and Machine Learning

12. xx

13.

APPENDIX

A. Setting Up Python Programming Environment

Chapter 5: Graphical User Interfaces

Note: Mac Users may want to download IDE “textwrangler” instead of “pyzo.”

All the scripts considered so far are either dialog-based user interactive or non-user interactive. Dialog-

based user interactive scripts guide users to respond to the prompted questions. An example of dialog-

based user interactive scripts can be found in Python statements. There are primitive two Python

statements for user interactions: input() and print(). For example,

name = input(“Enter your name: “)

The function input() gives a query prompt “Enter your name:” to users and takes a user’s typed

string value, which is then assigned to the variable name. Hence, the variable name is in String type, and

it holds the String value typed by a user. However, if you want to receive an integer, consider the following:

age = int(input(“Enter your age: “))

The function input() receives user entered value, which should be checked or converted to an integer.

For this outer function int() is used. If a user entered value is not an integer, it returns an error. If a float

number is entered, it is converted into an integer.

Similarly, function print() displays data to the standard output, which is the monitor. A simple example

is to say hello to users:

print(“Hello“)

There may be a special case that your Python script needs to display very lengthy text. Then, triple quotes

can be used. See the example below:

print(’’’Hello, Mercy College!

This is a sample user interface in Python statement. I am

not sure if you like it… A lengthy text

can be written and displayed if triple quotes are used

like this.’’’)

One-step advanced user-interactive programs are to use graphic components. Examples of graphic

components include buttons, textbox, labels, scroll bars, etc. The Python scripts that use graphic

components for user interactions are called graphical user interfaces- (GUI-) based script.

This chapter describes various ways of GUI-based Python scripting.

5.1 Graphic Components

The GUI module package provided by Python is called tkinter. The module tkinter should be

imported in scripts and the function Tk() instantiates a top level graphic component. Before discussing

about graphic components available in tkinter, we will consider a simple GUI example.

EXAMPLE 5.1: Recall a script, My7loopTemp.py, converting Celsius temperature to Fahrenheit

temperature in EXAMPLE 2.6. A similar computation can be displayed on GUI. Write a GUI script,

gui1temp.py, which can convert a given number to both Celsius and Fahrenheit.

(a) Initial GUI

(b) Click the Upper Button

(c) Clicking the Lower Button also

The script code is as follows:

Script gui1temp.py (1) from tkinter import *

(2) def convert2c():

(3) try:

(4) f = float(tempIN.get())

(5) c = (f -32)*5.0/9.0

(6) tempOUTc.set(c)

(7) except ValueError:

(8) pass

(9) def convert2f():

(10) try: (11) c = float(tempIN.get()) (12) f = c*9.0/5.0 +32 (13) tempOUTf.set(f) (14) except ValueError: (15) pass

(16) root = Tk() # the basic window, which is called here “root” is created. (17) f=root # to make the variable short, from “root” to “f” (18) root.title("Temperature Converter")

(19) tempIN = StringVar() (20) tempOUTc = StringVar() (21) tempOUTf = StringVar()

(22) Label(f, text="Enter a temperature and click a button to convert...").grid(columnspan=4,row=0,sticky=”w”)

(23) Entry(f, textvariable=tempIN, width=7).grid(column=0, rowspan=2, row=1, sticky=W)

(24) Button(f, text="in F to Convert =>", command=convert2c).grid(column=1, row=1, sticky=W)

(25) Button(f, text="in C to Convert =>", command=convert2f).grid(column=1, row=2, sticky=W)

(26) Label(f, textvariable=tempOUTc).grid(column=2, row=1, sticky=(W, E)) (27) Label(f, textvariable=tempOUTf).grid(column=2, row=2, sticky=(W, E)) (28) Label(f, text="in C").grid(column=3, row=1, sticky=W) (29) Label(f, text="in F").grid(column=3, row=2, sticky=W)

(30) root.mainloop()

As shown above, the module tkinter should be imported in line (1) to render the graphic components,

the classes Label, Entry, Button, etc. Those classes of graphic component are already defined and

provided. Note that Label is a Python class and Label() is in an object constructor form, in which form,

the class Label can be instantiated. What we can do in this example is to instantiate those classes. As a

class is instantiated, some specific options can be defined by using arguments. For example, Button

(root, fg=”red”, bg=”blue”), where foreground and background colors can be specified.

The module tkinter has classes, Tk and Tcl. The class Tk() can be instantiated with no argument as

shown in line (16). The two functions shown in lines (2)-(16) have been discussed in EXAMPLE 2.6. An

object of Tk() is called the root of this GUI, which is the master or parent window. The graphic

components of Label(), Entry() and Button() are contained in the master window, root. The

object of Tk() first invokes the title() method to display the title of the GUI window in line (18).

Renaming of a Tk() object in line(17) is redundant if the object reference root is used instead.

In order to refer the variables that are used in the logic of temperature conversions, the variables shown in

graphic components are declared in lines (20)-(22). tempIN, tempOUTf, and tempOUTc are the

variables holding the user input temperature, the conversion output to Fahrenheit, and the conversion

output to Celsius, respectively. Those graphic components are then organized in grid layout, 4 columns

and 3 rows.

On the first row, the text appears over those all four columns in left alignment by the statement sticky=W.

Columns are spanned by columnspan=4 in line (23). The second and third rows have four columns, the

input textbox, button to execute a conversion method, the output text, and the label to display the

temperature unit, from left to right. User input can be received by the Entry() class in line (24). Here the

variable tempIN is defined in this graphic component by textvariable=tempIN, which will be used

in conversion processes as shown in lines (4) and (11).

Then, two buttons are created in lines (25) and (26). As a button is clicked, a corresponding method is

executed as specified by command=convert2c and command=convert2f. In lines (27) and (28), the output

tempOUTf or tempOUTc of those temperature conversion methods is displayed. The value held in such

a variable is centralized in horizon alignment by sticky=(W,E). Finally, the units of temperature are

shown in the Label() objects.

All of these graphic components are continued to run by root.mainloop(). Detailed description about

tkinter can be found at https://docs.python.org/3.4/library/tkinter.html.

EXERCISE 5.1: Write a Python script, grid1temp2.py, which has a few additions to the script,

grid1temp.py in EXAMPLE 5.1. A sample run illustrates below:

The initial GUI shown above can be expanded as the conversion outcome is displayed.

Hint: Font and color can be defined as the class Entry and Label are instantiated. Note that the font

can defined for font face (e.g., Helvetica), size (e.g., 24) and style (e.g., bald), and the color can be

changed by adding fg=”#xxxxxx” for foreground color setting, which is a RGB code in Hex.

Hint: Use the function .format() to define a decimal place. If you have a variable num holding

23.9876586, the following statement will format it to be 23.99:

‘{:.2f}’.format(num)

In this way, the following GUI is possible.

5.2 Windows

The module tkinter provides a basic window by the constructor, Tk(). All graphical components can

be placed on this basic window. There are three ways of placing graphical components: (1) The basic

window can contain graphical components directly; (2) Canvas is placed on the basic window and it

contains graphical components; and (3) similarly, Frame is placed on the basic window and a frame object

contains graphical components. These are illustrated below:

(1) Graphical Components in Tk() Output of 01createNone02.py

(2) Canvas in Tk(), where a canvas object contains graphical

components Output of 01createCanvas01.py

(3) Frame in Tk(), where a frame object contains graphical

components

Output of

EXAMPLE 5.2: The Python file, back2gui01.py, defines a class to initialize a canvas. In the canvas, a

rectangle and a square are drawn, where those two objects meet in the center of the canvas. Also a circle

is drawn closer to the center. The source code is below:

Coding Source, back2gui01.py from tkinter import *

def initialize(w,h):

root = Tk()

radius = h/10

root.title("New Mercy GUI-1")

can = Canvas(root, bg="#1199fe", width=w,

height=h)

can.create_rectangle(30, 20, w/2,h/2)

can.create_rectangle(w/2-radius*3, h/2-

radius*3, w/2,h/2, fill="#FFFFFF")

can.create_oval(w/2-radius,h/2-radius,

w/2+radius*5,h/2+radius*5, fill="#ff7711")

can.pack()

root.mainloop()

maxBound = input("Enter the width and height:

")

splitVal = maxBound.split()

width = int(splitVal[0])

height = int(splitVal[1])

print("w and h: {0} and {1}".format(width,

height))

initialize(width, height)

Improved to Class Sample from tkinter import *

class myPoly (object):

def __init__ (self, tit, w,h):

#constructor

root = Tk()

self.radius = h/10

root.title(tit+" of John Yoon")

#self.can = Canvas(root, width=w,

height=h)

self.can = Canvas(root, bg="#1199fe",

width=w, height=h)

self.can.create_rectangle(30, 20,

w/2,h/2)

self.can.create_rectangle(w/2-

self.radius*3, h/2-self.radius*3, w/2,h/2,

fill="#FFFFFF")

self.can.create_oval(w/2-

self.radius,h/2-self.radius,

w/2+self.radius*5.5,h/2+self.radius*5.5,

fill="#ff7711")

self.can.pack()

root.mainloop()

def drawStar(self,w,h,k):

pass

maxBound = input("Enter the width and height:

")

splitVal = maxBound.split()

width = int(splitVal[0])

height = int(splitVal[1])

obj = ["myObj", "yourObj", "herObj", "hisObjt"]

for num, ob in enumerate(obj):

myObj of John Yoon

yourObj of John Yoon

herObj of John Yoon

hisObj of John Yoon

ob = myPoly(ob,width - num*50, height -

num*50)

EXERCISE 5.2: Recall the Python, back2gui01.py, to extend to write a Python script,

back2gui02class.py, which defines a function called drawStar, which will be one of the functions

associated with the class. A star should be inside the circle, its size should be proportional to the size of

the circle, which is also proportional to the size of the canvas. Create a list of four strings, “myObj”,

“yourObj”, “herObj” and “hisObj”. For each of these list element, an object of the class is constructed in

a canvas, whose size is reducing by 50 pixels. The title of each window should be one of the list element

followed by your name. For example, the biggest window will be “myObj of John Yoon”. A sample run

is shown below for the user input values, 700 500:

In what follows, frame objects are illustrated: one frame contains one or more inner frames which contain

deeper inner frames. Each frame may then contain graphical components such as Menus.

EXERCISE 5.3: Write a Python script, 04canvasDraw13boxArcPolysTxtOptim.py, which

draws n polygons for given size of windows. Depending on the width and height of windows, the size of

each polygon is determined. In all cases, the number of polygons is given at the command line. Polygons

begin from 0 angle, 1 angle, 2 angles, 3 angles, to the angle which is the given number minus one. The

number of polygons sitting each row is determined based on the smaller size between the width and the

height of the given window size. At the center position of each polygon, the number of its angles is

described. For example, a triangle has the label n=3 written at the center. Sample runs are illustrated below.

Command, python 04canvasDraw13boxArcPolysTxtOptim.py

500 300 15

Command, python 04canvasDraw13boxArcPolysTxtOptim.py 700

500 15

python

04canvasDraw13boxArcPolysTxtOptim.py

500 500 27

python 04canvasDraw13boxArcPolysTxtOptim.py

700 700 27

As tried with Frame, it is known that the layout of graphic components needs to be well designed. A Frame

can contain other sub-Frames, which in turn its sub-Frames. Those frames can be organized in a table, if

you can draw a table in your mind. We can place outer frame first and let the outer frame contain its inner

frames. If a frame contains multiple inner frames, the inner frames may be placed in a cell of the table

format of the outer frame. Consider EXAMPLE 5.2 below:

EXAMPLE 5.3: The following script, imgGUIstruct0.py, illustrates the source code on the left and

GUI windows on the right. The GUI layout is structured as follows:

In the coding source, the top window root contains three frames, topFrm, midFrm and btmFrm. The frame

in the middle, midFrm, contains two sub-frames, midLFrm and midRFrm. The bottom frame, btmFrm,

contains the label on the first row and the three subframes on the second row.

Coding Source, imgGUIstruct0.py from tkinter import *

def saveFile():

shoot.set("Sample SAVE button is clicked and so saved")

def loadFile():

shoot.set("Anything loaded? - Yea, nothing due to no

implementation")

def resetFile():

shoot.set("Reset")

root = Tk()

root.title("Layout Example")

root.geometry('{}x{}'.format(500,250))

topFrm = Frame(root, width=500, height=20)

midFrm = Frame(root, width=500, height=150)

btmFrm = Frame(root, width=500, height=80)

midLFrm = Frame(midFrm, width=250, height=150,

bg="#afafaf")

midRFrm = Frame(midFrm, width=250, height=150,

bg="#1187ff")

btmL = Frame(btmFrm, width=167, height=40,

bg="#ff87ff")

Initial Windows

btmC = Frame(btmFrm, width=167, height=40,

bg="#ff87ff")

btmR = Frame(btmFrm, width=167, height=40,

bg="#ff87ff")

topFrm.grid(row=0,sticky="w")

midFrm.grid(row=1)

midLFrm.grid(row=2,column=0)

midRFrm.grid(row=2,column=1)

btmFrm.grid(row=3)

btmL.grid(row=2,column=0)

btmC.grid(row=2,column=1)

btmR.grid(row=2,column=2)

shoot = StringVar()

Label(topFrm, text="Your Commentation").grid(row=0)

Label(btmFrm,

text="Execution:").grid(row=0,column=0 ,sticky="e")

lblTime = Label(btmFrm,

textvariable=shoot).grid(row=0,column=1,columnspan=2

,sticky="w")

saveBtn = Button(btmFrm, text="Save",

command=saveFile)

saveBtn.grid(row=2,column=0)

loadBtn = Button(btmFrm, text="Load",

command=loadFile)

loadBtn.grid(row=2,column=1)

resetBtn = Button(btmFrm, text="Reset",

command=resetFile)

resetBtn.grid(row=2,column=2)

root.mainloop()

After the Load button is clicked

EXERCISE 5.4: Write a Python script, tempConvGRUI_5.py, which uses multiple frames to convert

a given temperature to Celsius or to Fahrenheit. On the basic window of Tk() constructor, three frames are

constructed: upperFrame, midFrame and bottomFrame. The bottomFrame contains then two sub-frames:

bottom-leftFrame, and bottom-rightFrame. Those frames are labeled in a sample GUI below.

A sample GUI is shown below.

Temperature Converter

With the experience of using Frame() objects, the upper frame provides the text boxes to check

user credential. It asks users to enter login ID and password. The pairs of login ID and password

can be stored in many ways: 1) hard coded in the Python source, 2) hard coded in a third file,

and 3) a database containing the pairs. In this example, a hard coded data structure for login ID

and password pairs is a dictionary. The user entered login ID and password is checked as the

ones stored in a dictionary. Depending on the credential verification, the message will be

displayed on the lower frame. The value passing in Python with respect to a button click uses a

lambda function. For example, a button, if clicked, activates a function func() by passing

values, val1 and val2 in the following statement of button object construction:

Button (container, text=”Click”, command=lambda v1=val1, v2=val2:

func(v1,v2))

The identifiers in boldface are reserved words. The detailed source and sample execution is

provided below.

EXAMPLE 5.4: The following script, 06loginFrame1.py, illustrates the source code on the left and

GUI windows on the right. The GUI layout is a Frame-basis.

Coding Source, 06loginFrame1.py from tkinter import *

def createFrame(w,h):

root = Tk()

topF = Frame(root,width= w, height=h*0.1, bg="#000000")

upperF = Frame(root, width=w, height=h*0.2, bg="#cc585a")

middleF = Frame(root, width=w, height=h*0.4, bg="#ffffff")

lowerF = Frame(root, width=w, height=h*0.3, bg="#ff7711")

topF.grid(row=0)

upperF.grid(row=1)

middleF.grid(row=2)

lowerF.grid(row=3)

userID = StringVar()

userPass = StringVar()

Label(topF, text="Welcome to Mercy Cybersecurity", foreground="#ffffff",

background="#000000").grid(row=0, columnspan=4)

Label(upperF, text="Enter Your ID:", foreground="#000000",

background="#cc585a").grid(row=0,column=0)

usrid = Entry(upperF, textvariable=userID)

usrid.grid(row=0,column=1)

Label(upperF, text="Password:", foreground="#000000",

background="#cc585a").grid(row=0,column=2)

usrpass = Entry(upperF, textvariable=userPass)

usrpass.grid(row=0,column=3)

btnID = Button(upperF, text="log in", bg="#000000", fg="#ffffff",

command=lambda fram2s=lowerF: checkCredential(fram2s))

btnID.grid(row=0,column=4)

def checkCredential(fr):

global userID

u = usrid.get()

p = usrpass.get()

if u == "Yoon" and p == "John":

msg = Label(fr, text="Welcoming... "+u)

else:

msg = Label(fr, text="Invalid", fg="red")

msg.place(x=10,y=10)

root.mainloop()

createFrame(700,500)

Sample Execution

EXERCISE 5.5: Consider EXERCISE 5.4 and EXAMPLE 5.4. Write a Python script,

06loginFdoMore.py, which combines the two logics. If user’s credential is correct (from

EXAMPLE 5.4), show the temperature converter (from EXERCISE 5.4). The sample execution is shown

below:

When the credential is invalid:

When the credential is correct,

As a temperature is given and when each button is clicked:

It is also possible to combine Canvas and Frame in a Python program. Back to the previous

program, if a user credential is correct, the temperature converter is provided on Frame; if

invalid, an image is displayed on Canvas. From the package PIL, two modules are imported:

Image and ImageTk. The first, open an image by PIL.Image.open(); then

PIL.ImageTk.PhotoImage(), and then create_image() functions are used. With

understanding such functions, do the following exercise.

EXERCISE 5.6: Write a Python script, 06loginFdoMore2web.py, which extends EXERCISE 5.5

to display photo images. A sample execution is show below:

When a user credential is invalid:

When a user credential is correct:

5.3 Menus

The module tkinter provides extended widgets, e.g., Menu, referring to

http://www.tutorialspoint.com/python/tk_menu.htm. The following example illustrates a pulldown menu

where a specific menu is selected from the menu pulled-down and a corresponding method is executed.

EXAMPLE 5.5: Write a script, menu2pulldown0.py, that displays pull-down menus for file editing.

The following shows a sample coding and run.

Script menu2pulldown0.py (1) from tkinter import *

(2) import tkinter as tk

(3) from tkinter.filedialog import asksaveasfile

(4) from tkinter.filedialog import askopenfile

(5) root = tk.Tk()

(6) fram = tk.Frame(root, width=400, height=400)

(7) fram.pack_propagate(0)

(8) fram.pack(expand=YES, fill=BOTH)

(9) editor = tk.Text(fram)

(10) editor.pack_propagate (0) (11) editor.pack(expand=YES, fill=BOTH)

(12) root.title("Text Editor")

(13) def file_save(): (14) global editor (15) f = asksaveasfile(mode='w', defaultextension=".txt") (16) if f is None: # asksaveasfile return `None` if dialog closed with "cancel". (17) return (18) text2save = str(editor.get(1.0, END)) # starts from `1.0`, not `0.0` (19) f.write(text2save) (20) f.close()

(21) def createFile(): (22) print ("implement this")

(23) def openFile(): (24) print ("implement this")

(25) def getOut(): (26) root.quit()

(27) def explainHelp(): (28) helpwin = Toplevel (root) (29) button = Button (helpwin, text ="This is my first menu-driven Python program

\n" \

(30) " written for IASP 505.") (31) button.pack()

(32) myMenu = Menu(root)

(33) fileMenu = Menu (myMenu, tearoff=0) (34) fileMenu.add_command(label="New", command=createFile, accelerator="Ctrl+N") (35) fileMenu.add_command(label="Open...", command=openFile, accelerator="Ctrl+O") (36) fileMenu.add_command(label="Save", command=file_save, accelerator="Ctrl+S") (37) fileMenu.add_command(label="Save As...", command=file_save) (38) fileMenu.add_separator() (39) fileMenu.add_command(label="Exit", command=getOut)

(40) myMenu.add_cascade(label="File", menu=fileMenu)

(41) helpMenu = Menu (myMenu, tearoff=0) (42) helpMenu.add_command(label="View Help", command=createFile) (43) helpMenu.add_separator() (44) helpMenu.add_command(label="About Notepad", command=explainHelp) (45) myMenu.add_cascade(label="Help", menu=helpMenu)

(46) root.config (menu=myMenu) (46) root.mainloop ()

Output from c:\python34\python menu2pulldown0.py Initial Windows with “Saving As” menu

Then, the following is popped up to create and

save a file:

Then, the file is created and saved.

The top level master window, called root, is instantiated by Tk(). From the master windows, Frame()is

instantiated in line (6). Text() is instantiated within the frame instance in line (9), meaning that a Text

instance, editor, is contained in a Frame instance, fram. Similarly, Menu is instantiated in line (32).

The instance myMenu has fileMenu in line (40) and helpMenu in line (45) in a cascading alignment,

and then myMenu object is contained in the master window where Fram is available in line (46). Each

menu, fileMenu and helpMenu is created in lines (33) and (41), respectively. Pulldown menus are listed in

each menu. For example, submenus about files are added to fileMenu as shown in lines (34)-(37) and line

(39). In between, a separate line is added as shown in line (38).

The screen of a sample run is captured. The left screenshot shows how to edit and save it in a file. As the

submenu “Save As” is selected, the windows explorer is popped up where you can change directory and

name a file to save. In an example, the file saved is 1stSaving.txt in the upper right screenshot, which

appears in the windows explorer in the lower right screenshot.

EXERCISE 5.7: Write a Python script, menu2pulldn.py to complete methods, createFile() and

openFile(). Note that do not worry about the menus, Edit, Format, View, but complete File only.

EXAMPLE 5.6: Write a script, search_tkText.py, that takes a keyword from Entry(), and find all

matches from the bottom text box. All matched words in the text box are now highlighted in red. The

following shows a sample code and run.

Script search_tkText.py (1) from tkinter import *

(2) root = Tk()

(3) def match():

(4) article.tag_remove('matched', '1.0', END)

(5) article.tag_configure('matched', foreground='red', background='yellow')

(6) kk = key.get()

(7) if kk:

(8) lastIndx = '1.0'

(9) while True:

(10) indx = article.search(kk, lastIndx, nocase=1, stopindex=END)

(11) if not indx: break

(12) lastIndx = '%s+%dc' % (indx, len(kk))

(13) article.tag_add('matched', indx, lastIndx)

(14) fram = Frame(root)

(15) Label(fram,text='Keyword:').pack(side=LEFT)

(16) key = Entry(fram)

(17) key.pack(side=LEFT, fill=BOTH, expand=1)

(18) btnMatch = Button(fram, text='Match')

(19) btnMatch.pack(side=RIGHT)

(20) fram.pack(side=TOP)

(21) article = Text(root)

(22) article.insert('1.0',"You may enter/override an article here ...")

(23) article.pack(side=BOTTOM)

(24) btnMatch.config(command=match) (25) root.mainloop()

Output from c:\python34\python search_tkText.py Initial Windows after a few sentences are added

Highlighted matched words

In this example, a Text component is created and located bottom in the window as shown in lines (21) and

(23). An initial text is given in line (22).

The key coding block in this example is the function for search and highlight in lines (3)-(13). Entry and

Text are instantiated to object references, key and article, to read keyword and to read and match a full

text, respectively. In line (6), a keyword which is entered by users is read. Note that a Text instance can

invoke the method (or function), search() in line (10), which will then return the index (or the position)

of a matched word. A text object can invoke the method search() by arguments starting a search

keyword, a start position followed by variable and value pairs, for example, nocase=0 for case sensitive;

nocase=1 for case nonsensitive; stopindex=END for searching all the way to the end of the text. Then,

the method returns the start column position of the matched word. This position number is held by a

variable indx in line (10) for example.

If no matched, meaning that indx is null, then the while loop stops.

With the starting position of a matched word, line (12) computes the ending position of the matched word.

In line (13), these two numbers, starting and ending positions, a new tag which is highlighted according to

the configuration in line (5).

For detailed explanation on the Text wedget, please check out the website:

http://effbot.org/tkinterbook/text.htm.

It is possible that the menu and graphic components are contained in the same root windows. The following

example illustrates how they can be combined together to display GUI more effectively.

EXERCISE 5.8: Write a Python script, menu2pulldn4search.py to extend menu2pulldown.py

to render an image file. A sample run is as follows:

There are four pulldown menus: Keyword, Search, Article and Help. Both Keyword and Article can open

two different files. The Search menu read the text from the left text box. Each keyword in the left text box

is searched from the text in the right text box. If matched, the word in the right text box is highlighted in

red.

5.4 Animation

One of dynamic Python GUI program is an animation. Python can simulate animations in various ways.

One or more Python packages or modules may be used to simulate animations. For example, the

matplotlib package plots animations. Another example is to use the time module, which ticks the

movement of objects. The following illustrates an animation of using the time module.

Python source bubbleAnimation.py Execution for animation

EXERCISE 5.9: Write a Python script, anima3bouncing.py to roll a ball in all direction for every

different angles. The ball should be bounced at each of the boundaries, left, right, top and bottom

boundaries. A sample execution video tape is available on cysecure.org/505/index and its run is as follows:

5.5 Applications

In this section, one of the GUI programs that can access webpages and searches keywords is illustrated.

Let’s first see the steps of a run.

The given initial GUI has four of the pulldown menus on top, which appears on the left. The first keyword

menu can open a keyword file and display a set of keywords on the right below.

Similarly, the second pulldown menu can list the URLs from a file that is selected from the windows

explorer. Of the list, only highlighted URLs are accessed and the webpages are fetched. To access a given

web site, the module lib.parse needs to be imported. Then, a given URL, a method, urllib.request.urlopen(a

url) returns the HTML content of the url.

Since webpages are written in HTML, they can be converted into plaintext. Web contents in text are then

displayed on the right.

We may import a module, BeautifulSoup4 to convert HTML code to text. Of a few ways, you may

download and install using pip install BeautifulSoup4. BeautifulSoup is instantiated with a given HTML

file will be an object holding the converted text.

Then, against the web contents on the right, a search with the keyword will be conducted. Only matched

words are highlighted in the web contents on the left. In the pulldown menu of Search, the Statistics is

shown on the bottom row as shown on the right.

The third column content can then be stored in a file.

Script gui1temp.py (1) from tkinter import *

(2) import tkinter as tk

(3) from tkinter.filedialog import asksaveasfile

(4) from tkinter.filedialog import askopenfile

(5) import urllib.request

(6) from bs4 import BeautifulSoup as bs

(7) root = tk.Tk()

(8) root.title("Search Articles")

(9) Label(root,text="The feature of this program includes \

(10) 1) Scraping webpage text for a URL \ (11) 2) Reading web URLs from a file \ (12) 3) Reading search keywords from a file \ (13) ", bg="#ff9911").grid(columnspan=4,row=0,sticky=W)

(14) search = tk.Text(root, width=20, height=40) (15) search.grid(column=0,row=1,sticky=W)

(16) url = tk.Text(root, width=30, height=40) (17) url.grid(column=1,row=1,sticky=(W,E))

(18) article = tk.Text(root, width=60, height=40) (19) article.grid(column=2,row=1)#,sticky=W)

(20) cntOUT=StringVar() (21) tk.Label(root,text="Statistics: total").grid(column=0,row=2, sticky=W) (22) tk.Label(root, textvariable=cntOUT).grid(column=1,row=2,sticky=W) (23) tk.Label(root,text="found").grid(column=2,row=2, sticky=W)

# scroll bar can be defined here

(24) def appendKey(): # implement here

(25) def createKey(): (26) search.delete(1.0,END)

(27) def openKey(): (28) global search (29) f = askopenfile(mode='r') (30) if f is None: (31) return (32) text2open = str(f.read()) (33) search.insert(INSERT,text2open)

(34) def createURL(): (35) url.delete(1.0,END)

(36) def openURL(): (37) global aurl (38) f = askopenfile(mode='r') (39) if f is None: (40) return (41) text2open = str(f.read()) (42) url.delete(1.0,END) (43) url.insert(INSERT,text2open)

(44) def createFile(): (45) article.delete(1.0,END)

(46) def file_save(): # implement here

(47) def readAll(): # implement here

(48) def readOne(): (49) global article (50) article.delete(1.0,END) (51) readAddr = str(url.selection_get()) (52) for ur in readAddr.split(): (53) urladdr = "http://"+ur (54) print (urladdr) (55) urladd = "----------------" + urladdr + "----------------" (56) article.insert(END,urladd) (57) htmlFile = urllib.request.urlopen(urladdr) (58) soup = bs(htmlFile) (59) article.insert(END,soup.get_text())

(60) def caseHighlight(): # implement here

(61) def nocaseHighlight(): # implement here

(62) def searchStatistic(): (63) global cnt (64) try: (65) cntOUT.set(cnt) (66) except ValueError: (67) pass

(68) def getOut(): (69) print("Good-bye") (70) root.quit()

(71) def explainHelp(): (72) helpwin = Toplevel (root) (73) button = Button (helpwin, text ="This is a sample program \n" \ (74) " written for IASP 505.") (75) button.pack()

(76) myMenu = Menu(root)

(77) keyMenu= Menu (myMenu, tearoff=0)

(78) keyMenu.add_command(label="New", command=createKey, accelerator="Ctrl+N") (79) keyMenu.add_command(label="Open...", command=openKey, accelerator="Ctrl+O") (80) keyMenu.add_separator() (81) keyMenu.add_command(label="Exit", command=getOut) (82) myMenu.add_cascade(label="Keyword", menu=keyMenu)

(83) urlMenu= Menu (myMenu, tearoff=0) (84) urlMenu.add_command(label="New", command=createURL, accelerator="Ctrl+N") (85) urlMenu.add_command(label="Open...", command=openURL, accelerator="Ctrl+O") (86) myMenu.add_cascade(label="URL", menu=urlMenu)

(87) artiMenu= Menu (myMenu, tearoff=0) (88) artiMenu.add_command(label="Fetch Selected", command=readOne, accelerator="Ctrl+O") (89) artiMenu.add_command(label="Fetch All", command=readAll, accelerator="Ctrl+S") (90) artiMenu.add_command(label="Save As...", command=file_save) (91) artiMenu.add_separator() (92) artiMenu.add_command(label="Page Setup...", command=createFile) (93) artiMenu.add_command(label="Print...", command=createFile, accelerator="Ctrl+P") (94) artiMenu.add_separator() (95) artiMenu.add_command(label="Exit", command=getOut) (96) myMenu.add_cascade(label="WebPage", menu=artiMenu)

(97) srchMenu= Menu (myMenu, tearoff=0) (98) srchMenu.add_command(label="Case-sensitive", accelerator="Ctrl+io",

command=caseHighlight)

(99) srchMenu.add_command(label="All Matches", accelerator="Ctrl+io", command=nocaseHighlight) (100) srchMenu.add_separator()

(101) srchMenu.add_command(label="Statistics", accelerator="Ctrl+ix",

command=searchStatistic)

(102) myMenu.add_cascade(label="Search", menu=srchMenu)

(103) helpMenu= Menu (myMenu, tearoff=0)

(104) helpMenu.add_command(label="View Help", command=createFile)

(105) helpMenu.add_separator()

(106) helpMenu.add_command(label="About Notepad", command=explainHelp)

(107) myMenu.add_cascade(label="Help", menu=helpMenu)

(108) root.config (menu=myMenu)

(109) root.mainloop ()

EXERCISE 5.10: Recall EXAMPLE 5.2. As an extension, write the Python script,

imgGUIstruct2.py, which displays images: one on the left and another on the right. A sample run is

shown below. Note that two windows are initially open: one in Canvas and another in Frame.

Window 1: Images loaded on Canvas

Window 2: Frames with Buttons and Labels

EXERCISE 5.11: Extend EXERCISE 5 6 to add a few more features to the Python script,

menu2pulldn5webRE.py:

Regular Expression is supported

A list of URLs keeps increasing by reading webpages

The number of URLs extracted and the number of webs retrieved are counted

Scroll bars are provided for both URLs and Webpages

A sample run is illustrated bellows: