Python snippets

# colourHexSpiral.py

import turtle

colours = ['red', 'purple', 'blue', 'green', 'yellow', 'orange']

t = turtle.Pen()

t.reset()

t.speed(0) 

turtle.bgcolor('black')

for x in range(360):

    t.pencolor(colours[x%6])

    t.width(x/100+1)

    t.forward(x)

    t.left(59)  

# Keep screen displayed 

turtle.mainloop()

# textFileIO.py

filename = 'mytextfile.txt'

f1 = open(filename, 'wt') # open text file for writing

f1.write('The quick brown fox jumps over the lazy dog.' + '\n')

f1.write('Now is the time for citizens to come the the aid of their party.' + '\n')

f1.close()

f2 = open(filename, 'at') # open same file to append data

f2.write('A stitch in time saves nine.' + '\n')

f2.close()

f3 = open(filename, 'rt') # open same file for reading

data = f3.read()

f3.close()

lines = data.split('\n')

for line in lines: # print all lines in file

    print(line)

# saveLoadSettings.py

import configparser

def updateConfig(filespec, cfObject):

with open(filespec, 'w') as configfile:

cfObject.write(configfile)

#--- First write a new config file ---------------------------------------------

config = configparser.ConfigParser()

config['Paths'] = {}

config['Paths']['Input'] = '/home/pi/Documents/Input'

config['Paths']['Output'] = '/home/pi/Documents/Output'

config['General'] = {}

config['General']['Updated'] = '25/12/2020'

filespec = 'settings.ini'

updateConfig(filespec, config)

print('Config file written: ' + filespec) 

#--- Now read whats in config file ---------------------------------------------

config = configparser.ConfigParser()

config.read(filespec)

print(config.sections())

print(config['Paths']['Input'])

print(config['Paths']['Output'])

print(config['General']['Updated'])

# --- Change config value and update config file -------------------------------

config['General']['Updated'] = '26/12/2020'

updateConfig(filespec, config)

print('Updated config file: ' + filespec) 

#--- Now read whats in updated config file--------------------------------------

config = configparser.ConfigParser()

config.read(filespec)

print(config['General']['Updated'])

''' Sample settings file - settings.ini

[Paths]

input = /home/pi/Documents/Input

output = /home/pi/Documents/Output

[General]

updated = 26/12/2020

'''

# sorting.py

# sorting Lists using the sort() method

fruits = []

fruits.append('lemon')

fruits.append('apple')

fruits.append('banana')

fruits.append('orange')

fruits.sort()

for fruit in fruits:

    print(fruit)

# sorting different data types using the sorted() function

# List 

x = ['q', 'w', 'r', 'e', 't', 'y'] 

print(sorted(x)) 

# Tuple 

x = ('q', 'w', 'e', 'r', 't', 'y') 

print(sorted(x)) 

# String-sorted based on ASCII translations 

x = "python"

print(sorted(x)) 

# Dictionary 

x = {'q':1, 'w':2, 'e':3, 'r':4, 't':5, 'y':6} 

print(sorted(x)) 

# Set 

x = {'q', 'w', 'e', 'r', 't', 'y'} 

print(sorted(x)) 

# Frozen Set 

x = frozenset(('q', 'w', 'e', 'r', 't', 'y')) 

print(sorted(x)) 

# parseXML.py

import xml.etree.ElementTree as ET 

''' Sample library.xml file

<?xml version="1.0" encoding="UTF-8"?>

<library>

    <book>

        <title>The War of the Worlds</title>

        <author>H. G. Wells</author>

        <genre>Science Fiction</genre>

    </book>

    ...

'''

def parseXML(xmlfile): 

    tree = ET.parse(xmlfile) 

    root = tree.getroot()  

    items = []               # make an empty list

    for item in root.findall('./book'):

        detail = {}          # make a dictionary for each item

        for child in item: 

                             # use xml tag as key to dictionary

            detail[child.tag] = child.text 

        items.append(detail) # add dictionary to item list

    return items             # return item list

# parse xml file 

filename = 'library.xml'

library = parseXML(filename)

for book in library:

    for key in book:

        text = book[key]

        print(f'{key:10} {text}')

    print()

# sinCosTan.py

import math

def getSinCosTan(angle):

    radians = math.radians(angle)

    print('Angle:', angle, 'is:', f'{radians:.3f}', 'Radians')

    sine    = math.sin(radians)

    cosine  = math.cos(radians)

    tangent = math.tan(radians)

    print('Sine    of Angle:', angle, 'is:', f'{sine:.3f}')

    print('Cosine  of Angle:', angle, 'is:', f'{cosine:.3f}')

    print('Tangent of Angle:', angle, 'is:', f'{tangent:.3f}')

    asine    = round(math.degrees(math.asin(sine)))

    acosine  = round(math.degrees(math.acos(cosine)))

    atangent = round(math.degrees(math.atan(tangent)))

    print('Inverse Sine    of:', f'{sine:.3f}',   'is:', asine)

    print('Inverse Cosine  of:', f'{cosine:.3f}', 'is:', acosine)

    print('Inverse Tangent of:', f'{tangent:.3f}','is:', atangent)

    print()

angle = 45

getSinCosTan(angle)

# getPermutations.py

from itertools import permutations 

letters = 'ABCDEFGHIJK'

for n in range(2,5):

    combos = list(permutations(letters[:n]))

    print(f'Letters: {letters[:n]}')

    print('Permutations')

    for tuple in combos:

        print(tuple)

    print()

print('Number of letters  Number of permutations')

print('-----------------  ----------------------')

for n in range(1,11):

    combos = list(permutations(letters[:n]))

    print(f'{len(letters[:n]):17} {len(combos):23}')

# timeCode.py

import time

def doSomething(limit):

    for n in range(limit):

        j = 3**n

print('Timing, please wait ...')        

tic = time.perf_counter()

doSomething(30000)

toc = time.perf_counter()

print(f'Seconds elapsed: {toc-tic:0.2f}')

import timeit

lines_of_code = """

def doSomething(limit):

    for n in range(limit):

        j = 3**n

doSomething(30000)

"""

times = 10 # number of times to test

average = timeit.timeit(lines_of_code, number = times)/times

print(f'Average seconds elapsed: {average:0.2f}')

# formattingDateTime.py

from datetime import datetime

import time

now = datetime.now()

print(f'now: {now}')

print(type(now))

print()

# breaking down datetime.now into components

print(f'formatted datetime: {now.day}/{now.month}/{now.year}' + \

                         f' {now.hour}:{now.minute}:{now.second}')

print()

# show time as a number

timeAsANumber = time.time()

print(f'timeAsANumber: {timeAsANumber}')

print(type(timeAsANumber))

print()

# formatting date and time using strftime()

print(datetime.fromtimestamp(timeAsANumber).strftime('%Y/%m/%d %H:%M:%S.%f'))

print(datetime.fromtimestamp(timeAsANumber).strftime('%Y/%m/%d %H:%M:%S'))

print(type(datetime.fromtimestamp(timeAsANumber)))

print()

for n in range(10):

    now = time.time()

    print(datetime.fromtimestamp(now).strftime('%S.%f'))

    time.sleep(0.1)

print()

# get future or past dates

import datetime

newYearsEve = datetime.datetime.strptime('31/12/2020', "%d/%m/%Y")

newYearsDay = newYearsEve + datetime.timedelta(days=1)

print(newYearsDay)

# can also use: microseconds, milliseconds, seconds, minutes, hours, days or weeks

# for a complete list of strftime formatting characters see: https://strftime.org

# usingOSmodule.py

import os

import time

# show current directory

curDir = os.getcwd()

print('Current Directory =', curDir)

# make a new directory

os.mkdir('newFolder')

# make a new file

f1 = open('newFile.txt', 'wt')

f1.close()

# rename file

os.rename('newFile.txt','oldFile.txt')

# list files and folders in current directory

fileList = os.listdir(curDir)

for entry in fileList:

    if os.path.isfile(entry):

        print('File:\t', entry)

    elif os.path.isdir(entry):

        print('Folder:\t', entry)

# get last modification date and time of file

secs = os.path.getmtime('oldFile.txt')

print('oldFile.txt last modified:', \

    time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(secs)))

# remove a file

os.remove('oldFile.txt')

# remove directory

os.rmdir('newFolder')

# issueOScommand.py

import subprocess

def issueOScommand(cmd):

    response = subprocess.check_output(cmd)

    response = response.decode("ascii") # needed in python 3

    return response

# construct command to be issued, together with its arguments / parameters

cmd = ['cmd.exe', '/C', 'dir']

# issue command and collect any output

output = issueOScommand(cmd)

# print lines from output

lines = output.split('\r\n')

for line in lines:

    print(line)

# show_command_line_arguments.py

import sys

# total arguments

n = len(sys.argv)

print("Total arguments passed:", n)

# Arguments passed

print("\nName of Python script:", sys.argv[0])

print("\nArguments passed:", end = " ")

for i in range(1, n):

    print(sys.argv[i], end = " ")

# listEnvironmentValues.py

import os

for var in os.environ:

    print(var + '=' + os.path.expandvars('$' + var))

# fileExplorer.py

import os

def walkDirectory(path):

    for directory, subdirectory, filenames in os.walk(path):

        if directory == path:

            print('Files\n-----')

            for filename in filenames:

                print(filename)

            print()

            print('Sub-Folders\n-----------')

        print(directory)

    print()

path = '.' # = current directory (or replace with full path)

walkDirectory(path)

# readWindowsRegistry.py

# Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion

from winreg import *

from datetime import datetime

registry = ConnectRegistry(None, HKEY_LOCAL_MACHINE)

def getRegistryEntry(strKey, strItem):

    rawKey = OpenKey(registry, strKey)

    found = False

    try:

        i = 0

        while 1:

            name, value, type = EnumValue(rawKey, i)

            if name == strItem:

                found = True

                break

            i += 1

    except WindowsError:

        pass

    CloseKey(rawKey)

    if found:

        return value

    else:

        return 'Not Found'

key = r'SOFTWARE\Microsoft\Windows NT\CurrentVersion'

productName  = getRegistryEntry(key, 'ProductName')

releaseId    = getRegistryEntry(key, 'ReleaseId')

installDate  = getRegistryEntry(key, 'InstallDate')

currentBuild = getRegistryEntry(key, 'CurrentBuild')

ubr          = getRegistryEntry(key, 'UBR')

installedOn = datetime.fromtimestamp(installDate).strftime('%d/%m/%Y')

print(f'Edition         {productName}')

print(f'Release         {releaseId}')

print(f'Installed on    {installedOn}')

print(f'OS build        {currentBuild}.{ubr}')

# plot2barCharts.py

from matplotlib import pyplot as plt

import numpy as np

x  = [1,2,3,4,5,6,7,8,9]

y  = [7,5,4,6,8,4,3,2,8]

y2 = [3,7,5,4,6,8,4,3,2]

ytype=['Pigs','Cows']

width = 0.35

pos = np.arange(len(x))

print('pos =', pos)

plt.bar(pos, y, width, color='b') 

plt.bar(pos+width, y2, width, color='g')

plt.ylabel('Cattle', fontsize=16)

plt.title('Farmyard animals sold',fontsize=18)

plt.legend(ytype,loc=2)

plt.show()

# minimal_pygame.py

# imports

import pygame

# functions

def update_screen():

    pygame.draw.rect(screen, RED, pygame.Rect(100, 200, 300, 400))

# variables

BLACK = (0,0,0)

RED   = (255,0,0)

# main

pygame.init()

DISPLAY_WIDTH = 600

DISPLAY_HEIGHT = 700

displaySize = (DISPLAY_WIDTH, DISPLAY_HEIGHT)

pygame.display.set_caption("Minimal Pygame")

screen = pygame.display.set_mode(displaySize)

screen.fill(BLACK)

clock = pygame.time.Clock()

done = False

while not done:

    for event in pygame.event.get():

        if event.type == pygame.QUIT: # window close button clicked

            done = True

        if event.type == pygame.KEYUP:

            if event.key == pygame.K_q: # 'q' key pressed

                done = True

    screen.fill(BLACK)

    update_screen()

    pygame.display.flip()

    clock.tick(60)

print('Quitting')

pygame.quit()

# minimal_tkinter.py

from tkinter import *

root = Tk()

root.title("Minimal Tkinter Example")

root.geometry("300x100")

def button_clicked(event):

    entry_text = my_entry.get()

    my_label.config(text = entry_text)

my_entry = Entry(root)

my_entry.pack()

my_entry.insert(0, "Enter any Text")

my_button = Button(root, text="Click this button to see what happens")

my_button.bind("<Button-1>", button_clicked)

my_button.pack()

my_label = Label(root, text='watch this label')

my_label.pack()

root.mainloop()

# drawGrid.py - Draws a grid of cells

import pygame

# Define dimensions of grid

DISPLAY_WIDTH = 640

DISPLAY_HEIGHT = 480

displaySize = (DISPLAY_WIDTH, DISPLAY_HEIGHT)

# Define size and number of cells

SIZE = 16

XCELLS = int(DISPLAY_WIDTH/SIZE)

YCELLS = int(DISPLAY_HEIGHT/SIZE)

# Constants for Left and Right Mouse button events

LEFT = 1

RIGHT = 3

# Create a list of colours

colours = []

colours.append((255, 255, 255))

colours.append((  0,   0,   0))

WHITE = 0

BLACK = 1

# Create a list for cells in the grid

grid = [[WHITE for y in range(YCELLS)] for x in range(XCELLS)]

# Define a function to initialise all the cells

def initGrid(grid, c):

    for y in range(YCELLS):

        for x in range(XCELLS):

            grid[x][y] = c

# Define a function to draw a square of colour(c) at coordinates, x and y

def drawCell(x, y, c):

    pygame.draw.rect(screen, colours[c], \

                     pygame.Rect(x * SIZE, y * SIZE, SIZE-1, SIZE-1))

# Define a function to update cells on screen from grid

def update():

    for y in range(YCELLS):

        for x in range(XCELLS):

            c = grid[x][y]

            drawCell(x, y, c)

# Initialise pygame

pygame.init()

# Set the window title

pygame.display.set_caption("Draw a grid of cells")

# Create the window

screen = pygame.display.set_mode(displaySize)

# Blank screen

screen.fill(BLACK)

# Initialise the generations

initGrid(grid, WHITE)

# Update the full display surface to the screen

pygame.display.flip()

# Create a clock to manage time

clock = pygame.time.Clock()

# Initialise variables

done = False

drawingON = False

drawColour = WHITE

# Runs the game loop

while not done:

    # The code here runs when every frame is drawn

    # Get any events that have occurred, like close button(X) clicked

    for event in pygame.event.get():

        if event.type == pygame.QUIT:

            done = True

        # handle Mouse

        if event.type == pygame.MOUSEBUTTONDOWN:

            drawingON = True

            if event.button == LEFT:

                drawColour = BLACK

            elif event.button == RIGHT:

                drawColour = WHITE

        if event.type == pygame.MOUSEBUTTONUP:

            drawingON = False

        # Check for q key

        if event.type == pygame.KEYUP:

            if event.key == pygame.K_q:

                done = True

    # Check for drawingON

    if drawingON:

        pos = pygame.mouse.get_pos()

        x = int(pos[0] / SIZE)

        y = int(pos[1] / SIZE)

        grid[x][y] = drawColour

    # Update and draw 

    update()

    # Update the full display surface to the screen

    pygame.display.flip()

    # Limit the game to 30 frames per second

    clock.tick(60)

print('Quitting')

pygame.quit()

# getWebPage.py

import requests

def getWebPage(url):

    headers = {'User-Agent': user_agent}

    response = requests.get(url,headers=headers)

    html = response.content

    return html.decode()

url = 'https://sites.google.com/site/getthecodingbug/courses/pythonsnippets'

user_agent = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.47 Safari/537.36'

html = getWebPage(url)          # this page

tags = html.replace('<', '>')   # split html into tags

tags = tags.split('>')

# Find Table Of Contents (TOC) tags

n = 0

for tag in tags:

    if 'getWebPage.py' in tag:

        break

    if 'a name="TOC-' in tag:

        print(f'{tag:60} {tags[n+5]:40}')

    n += 1