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Starting Python

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Re: Starting Python

#61

Jun 15th, 2006

If you bind GUI event to a function you use a callback function, alas, callback functions are not allowed to have arguments. To remedy situation you can use currying or lambda. Here is an examples of both:

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 Python Syntax (Toggle Plain Text) 
# currying allows GUI callback functions to have arguments
# an alternative is lambda
 
from Tkinter import *
 
class Curry:
    """adds arguments to callback function"""
    def __init__(self, callback, *args, **kwargs):
        self.callback = callback
        self.args = args
        self.kwargs = kwargs
 
    def __call__(self):
        # needs Python23 or higher
        return self.callback(*self.args, **self.kwargs)
 
def callback(what=None):
    print "callback =", what  # for testing
    if what == 'red':
        b1.config(bg="#ff0000")
    if what == 'blue':
        b2.config(bg="#0000ff")
 
root = Tk()
 
# uses class Curry, since command=callback("red") will not work
b1 = Button(root, text="red", width=6, command=Curry(callback, "red"))
b1.pack(side=LEFT, padx=2, pady=2)
 
# uses lambda instead of Curry
b2 = Button(root, text="blue", width=6, command=lambda: callback("blue"))
b2.pack(side=LEFT, padx=2, pady=2)
 
mainloop()
# currying allows GUI callback functions to have arguments
# an alternative is lambda

from Tkinter import *

class Curry:
    """adds arguments to callback function"""
    def __init__(self, callback, *args, **kwargs):
        self.callback = callback
        self.args = args
        self.kwargs = kwargs

    def __call__(self):
        # needs Python23 or higher
        return self.callback(*self.args, **self.kwargs)

def callback(what=None):
    print "callback =", what  # for testing
    if what == 'red':
        b1.config(bg="#ff0000")
    if what == 'blue':
        b2.config(bg="#0000ff")

root = Tk()

# uses class Curry, since command=callback("red") will not work
b1 = Button(root, text="red", width=6, command=Curry(callback, "red"))
b1.pack(side=LEFT, padx=2, pady=2)

# uses lambda instead of Curry
b2 = Button(root, text="blue", width=6, command=lambda: callback("blue"))
b2.pack(side=LEFT, padx=2, pady=2)

mainloop()

Editor's Note:
command uses a function object rather then a function call, so arguments have to be added with a lambda or curry wrapper.

Last edited by vegaseat; Sep 22nd, 2006 at 7:03 pm. Reason: added more detail to Bumsfeld's explanation

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Re: Starting Python

#62

Jun 15th, 2006

The Python module threading allows you to run a function in the background, as your main program executes. This example adds another feature of Python, called function decoration, the @decorator is added to just above the function you want to run in the background, as example shows:

 Help with Code Tags 
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# running a function in the background with threading
# (apply threading to a function with a function @decorator)
 
import time
import threading
 
def background(f):
    def bg_f(*a, **kw):
        threading.Thread(target=f, args=a, kwargs=kw).start()
    return bg_f
 
# the @decorator forces this function to run in the background
@background
def counter(n):
    i = 0
    while i < n:
        print i
        i += 1
        time.sleep(0.5)  # 0.5 second delay
 
counter(7)
time.sleep(0.4)
print 'hello'   # prints hello, before counter prints 1 ...
time.sleep(1.2)
print 'world'   # prints world, before counter prints 4 ...
# running a function in the background with threading
# (apply threading to a function with a function @decorator)

import time
import threading

def background(f):
    def bg_f(*a, **kw):
        threading.Thread(target=f, args=a, kwargs=kw).start()
    return bg_f

# the @decorator forces this function to run in the background
@background
def counter(n):
    i = 0
    while i < n:
        print i
        i += 1
        time.sleep(0.5)  # 0.5 second delay

counter(7)
time.sleep(0.4)
print 'hello'   # prints hello, before counter prints 1 ...
time.sleep(1.2)
print 'world'   # prints world, before counter prints 4 ...

Output looks like:

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
0
hello
1
2
3
world
4
5
6
0
hello
1
2
3
world
4
5
6

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Re: Starting Python

#63

Jun 17th, 2006

Here is an example of how you could use Tkinter, a loop, counter, and some other stuff. Here is the program code:

 Help with Code Tags 
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#Created by Mattamus Prime (AKA Matt Tacular)
#This is a simple dice program, pretends to roll a die and show you the progress
#After 25 random screens, it picks one to show.
 
import random
from Tkinter import *
import time
 
def clear():
    answerLabel2.configure(text="")
    answerLabel3.configure(text="")
    answerLabel4.configure(text="")
    mainWindow.update()
 
def aDie():
    infiniteLoop = True
    counter = 0
    while infiniteLoop:
        number = random.randint(1,6)
        time.sleep(0.1)
        clear()
        counter += 1
        if number == 1:
            strDie2 = "I              I"
            strDie3 = "I      II      I"
            strDie4 = "I              I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 2:
            strDie2 = "I    II        I"
            strDie3 = "I              I"
            strDie4 = "I        II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 3:
            strDie2 = "I        II    I"
            strDie3 = "I      II      I"
            strDie4 = "I    II        I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 4:
            strDie2 = "I    II  II    I"
            strDie3 = "I              I"
            strDie4 = "I    II  II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 5:
            strDie2 = "I    II  II    I"
            strDie3 = "I      II      I"
            strDie4 = "I    II  II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 6:
            strDie2 = "I    II  II    I"
            strDie3 = "I    II  II    I"
            strDie4 = "I    II  II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        if counter == 25:
            break
        mainWindow.update()
mainWindow = Tk()
 
startButton = Button(mainWindow, text="Roll", command=aDie, width=20)
startButton.grid(row=0, column=0)
 
answerLabel = Label(mainWindow, text="IIIIIIIIIIIIIIII", width=20)
answerLabel.grid(row=1, column=0)
 
answerLabel2 = Label(mainWindow, text="I              I", width=20)
answerLabel2.grid(row=2, column=0)
 
answerLabel3 = Label(mainWindow, text="I              I", width=20)
answerLabel3.grid(row=3, column=0)
 
answerLabel4 = Label(mainWindow, text="I              I", width=20)
answerLabel4.grid(row=4, column=0)
 
answerLabel5 = Label(mainWindow, text="IIIIIIIIIIIIIIII", width=20)
answerLabel5.grid(row=5, column=0)
 
mainWindow.mainloop()
#Created by Mattamus Prime (AKA Matt Tacular)
#This is a simple dice program, pretends to roll a die and show you the progress
#After 25 random screens, it picks one to show.

import random
from Tkinter import *
import time

def clear():
    answerLabel2.configure(text="")
    answerLabel3.configure(text="")
    answerLabel4.configure(text="")
    mainWindow.update()
    
def aDie():
    infiniteLoop = True
    counter = 0
    while infiniteLoop:
        number = random.randint(1,6)
        time.sleep(0.1)
        clear()
        counter += 1
        if number == 1:
            strDie2 = "I              I"
            strDie3 = "I      II      I"
            strDie4 = "I              I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 2:
            strDie2 = "I    II        I"
            strDie3 = "I              I"
            strDie4 = "I        II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 3:
            strDie2 = "I        II    I"
            strDie3 = "I      II      I"
            strDie4 = "I    II        I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 4:
            strDie2 = "I    II  II    I"
            strDie3 = "I              I"
            strDie4 = "I    II  II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 5:
            strDie2 = "I    II  II    I"
            strDie3 = "I      II      I"
            strDie4 = "I    II  II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        elif number == 6:
            strDie2 = "I    II  II    I"
            strDie3 = "I    II  II    I"
            strDie4 = "I    II  II    I"
            answerLabel2.configure(text=strDie2)
            answerLabel3.configure(text=strDie3)
            answerLabel4.configure(text=strDie4)
            number = random.randint(1,6)
        if counter == 25:
            break
        mainWindow.update()
mainWindow = Tk()
    
startButton = Button(mainWindow, text="Roll", command=aDie, width=20)
startButton.grid(row=0, column=0)

answerLabel = Label(mainWindow, text="IIIIIIIIIIIIIIII", width=20)
answerLabel.grid(row=1, column=0)

answerLabel2 = Label(mainWindow, text="I              I", width=20)
answerLabel2.grid(row=2, column=0)

answerLabel3 = Label(mainWindow, text="I              I", width=20)
answerLabel3.grid(row=3, column=0)

answerLabel4 = Label(mainWindow, text="I              I", width=20)
answerLabel4.grid(row=4, column=0)

answerLabel5 = Label(mainWindow, text="IIIIIIIIIIIIIIII", width=20)
answerLabel5.grid(row=5, column=0)

mainWindow.mainloop()

What I did, was made a window in Tkinter and in that window made a "Roll" Button. then there are 5 blank labels that get filled by different lines of IIII's depending on what number from 1 - 6 is chosen.

This also shows how you can set up a loop that only ends when the counter hits a certain number, and that only happens when the die has displayed a certain amount of numbers.

And if you want it to run the window with no console, save the code as "filename.pyw" instead of "filename.py"

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Re: Starting Python

#64

Jun 17th, 2006

You have seen those animated GIF files on webpages, wiggling and jiggling, sometimes fun, sometimes annoyance. I wanted an animated GIF file to animate on Tkinter, but only got a still picture.

An animated GIF file is really just a series of GIF files, like a series of frames in a movie. You can take one of the common GIF Animator Utlities and extract the individual GIF files that make up the series.

Next, loop these image files through the regular canvas.create_image() function, delay each frame to mimic animation, and you have your custom made movie. Here is the code example ...

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
# mimic an animated GIF displaying a series of GIFs
# (an animated GIF was used to create the series of GIFs with a common GIF animator utility)
 
import time
from Tkinter import *
 
root = Tk()
 
imagelist = ["dog001.gif","dog002.gif","dog003.gif","dog004.gif","dog005.gif","dog006.gif","dog007.gif"]
 
# extract width and height info
photo1 = PhotoImage(file=imagelist[0])
width1 = photo1.width()
height1 = photo1.height()
canvas1 = Canvas(width=width1, height=height1)
canvas1.pack()
 
# loop through the series of GIFs
for k in range(0, 1000):
    print imagelist[k%7], k # test only
    photo1 = PhotoImage(file=imagelist[k%7])
    canvas1.create_image(width1/2.0, height1/2.0, image=photo1)
    canvas1.update()
    time.sleep(0.1)
 
root.mainloop()
# mimic an animated GIF displaying a series of GIFs
# (an animated GIF was used to create the series of GIFs with a common GIF animator utility)
 
import time
from Tkinter import *
 
root = Tk()
 
imagelist = ["dog001.gif","dog002.gif","dog003.gif","dog004.gif","dog005.gif","dog006.gif","dog007.gif"]
 
# extract width and height info
photo1 = PhotoImage(file=imagelist[0])
width1 = photo1.width()
height1 = photo1.height()
canvas1 = Canvas(width=width1, height=height1)
canvas1.pack()
 
# loop through the series of GIFs
for k in range(0, 1000):
    print imagelist[k%7], k # test only
    photo1 = PhotoImage(file=imagelist[k%7])
    canvas1.create_image(width1/2.0, height1/2.0, image=photo1)
    canvas1.update()
    time.sleep(0.1)
 
root.mainloop()

I have attached a small zip file containing the set of individual pictures that make up the animated GIF.

Last edited by vegaseat; May 15th, 2007 at 7:49 pm. Reason: php tags don't work any longer

Attached Files

Tk_AnimatedGIF1.zip (9.0 KB, 28 views)

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Re: Starting Python

-1

#65

Jun 28th, 2006

Display the letters in a text sorted by their frequency of occurance:

 Help with Code Tags 
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import string
 
# create a list of lower case letters
# ['a', 'b', 'c', 'd', 'e', ... ]
alpha_list = list(string.lowercase)
 
text = """The Spell Checker Poem ...
 
Eye halve a spelling chequer
It came with my pea sea
It plainly marques four my revue
Miss steaks eye kin knot sea.
 
Eye strike a key and type a word
And weight four it two say
Weather eye am wrong oar write
It shows me strait a weigh.
As soon as a mist ache is maid
It nose bee fore two long
And eye can put the error rite
Its rare lea ever wrong.
 
Eye have run this poem threw it
I am shore your pleased two no
its letter perfect awl the weigh
My chequer tolled me sew.
"""
 
# convert text to all lower case letters
text = text.lower()
 
# create a list of (frequency, letter) tuples
tuple_list = []
for letter in alpha_list:
    tuple_list.append((text.count(letter), letter))
 
# sort by frequency (high value first)
tuple_list.sort(reverse=True)
#print tuple_list
 
# show all letters with frequency above 0
for freq, letter in tuple_list:
    if freq > 0:
        print letter, freq
 
"""
result =
e 67
t 33
a 32
r 29
s 26
...
 
"""
import string
 
# create a list of lower case letters
# ['a', 'b', 'c', 'd', 'e', ... ]
alpha_list = list(string.lowercase)
 
text = """The Spell Checker Poem ...
 
Eye halve a spelling chequer
It came with my pea sea
It plainly marques four my revue
Miss steaks eye kin knot sea.
 
Eye strike a key and type a word
And weight four it two say
Weather eye am wrong oar write
It shows me strait a weigh.
As soon as a mist ache is maid
It nose bee fore two long
And eye can put the error rite
Its rare lea ever wrong.
 
Eye have run this poem threw it
I am shore your pleased two no
its letter perfect awl the weigh
My chequer tolled me sew.
"""
 
# convert text to all lower case letters
text = text.lower()
 
# create a list of (frequency, letter) tuples
tuple_list = []
for letter in alpha_list:
    tuple_list.append((text.count(letter), letter))
 
# sort by frequency (high value first)
tuple_list.sort(reverse=True)
#print tuple_list
 
# show all letters with frequency above 0
for freq, letter in tuple_list:
    if freq > 0:
        print letter, freq
 
"""
result =
e 67
t 33
a 32
r 29
s 26
...
 
"""

Moderator's note: php tags didn't work properly, replaced them.

Last edited by vegaseat; May 15th, 2007 at 7:53 pm. Reason: php tags changed

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Re: Starting Python

-1

#66

Jul 18th, 2006

Really nice sharings here .... thanks i hope it will continue

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Re: Starting Python

#67

Jul 21st, 2006

This short code finds all files in a given drive or folder/directory that end with a selected file extension. It also checks all the subdirectories:

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import os
 
# pick a folder or drive
folder = 'C:\\'
# pick a file extension
extension = ".css"
 
print "All files in %s ending with %s :" % (folder, extension)
file_list = []
for (paths, dirs, files) in os.walk(folder):
    for file in files:
        if file.endswith(extension):
            # show progress
            print '.',
            file_list.append(os.path.join(paths, file))
 
print
 
for full_filename in file_list:
    print full_filename
import os
 
# pick a folder or drive
folder = 'C:\\'
# pick a file extension
extension = ".css"
 
print "All files in %s ending with %s :" % (folder, extension)
file_list = []
for (paths, dirs, files) in os.walk(folder):
    for file in files:
        if file.endswith(extension):
            # show progress
            print '.',
            file_list.append(os.path.join(paths, file))
 
print
 
for full_filename in file_list:
    print full_filename

Last edited by vegaseat; May 15th, 2007 at 7:59 pm. Reason: changed php tags

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Re: Starting Python

#68

Jul 25th, 2006

If you want to create a unique filename in a given folder use the Python module tempfile:

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import tempfile
 
# creates a random file (text=True is textfile, text=False is binary file)
ext = '.txt'
pfx = 'tmp'
dir = 'C:\\Temp'
filename = tempfile.mkstemp(suffix=ext, prefix=pfx, dir=dir, text=True)[1]
print filename  # eg. C:\Temp\tmpsnrfgk.txt
 
# test it ...
fout = open(filename, 'w')
fout.write("Just a text file")
fout.close()
import tempfile

# creates a random file (text=True is textfile, text=False is binary file)
ext = '.txt'
pfx = 'tmp'
dir = 'C:\\Temp'
filename = tempfile.mkstemp(suffix=ext, prefix=pfx, dir=dir, text=True)[1]
print filename  # eg. C:\Temp\tmpsnrfgk.txt

# test it ...
fout = open(filename, 'w')
fout.write("Just a text file")
fout.close()

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Re: Starting Python

#69

Jul 28th, 2006

So, you want to know the operating system your computer has? This short Python code can tell you:

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import sys
 
operating_system = sys.platform
print operating_system              # eg.  win32
 
if operating_system[:3] == 'win':
    print "Your OS is Windows"
elif operating_system[:5] == 'linux':
    print "Your OS is Linux"
 
# or ........
 
import os
 
print os.name              # eg.  nt
print os.environ['OS']   # eg.  Windows_NT
import sys

operating_system = sys.platform
print operating_system              # eg.  win32

if operating_system[:3] == 'win':
    print "Your OS is Windows"
elif operating_system[:5] == 'linux':
    print "Your OS is Linux"

# or ........

import os

print os.name              # eg.  nt
print os.environ['OS']   # eg.  Windows_NT

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Re: Starting Python

#70

Aug 5th, 2006

This code allows you to create unique file names containing date and time that can be sorted by age:

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import time
 
# using year_month_day_hour_min_sec  (24 hour foemat)
filename1 = time.strftime('%Y_%m_%d_%H_%M_%S.dat')
print filename1  # eg.   2006_08_05_20_57_56.dat
 
# or using seconds since epoch
filename2 = str(int(time.time())) + ".dat"
print filename2  # eg.  1154825876.dat
import time

# using year_month_day_hour_min_sec  (24 hour foemat)
filename1 = time.strftime('%Y_%m_%d_%H_%M_%S.dat')
print filename1  # eg.   2006_08_05_20_57_56.dat

# or using seconds since epoch
filename2 = str(int(time.time())) + ".dat"
print filename2  # eg.  1154825876.dat

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