python 1

note to all programmers from other languages: indenting (using the TAB key) matters!

1. install
2. helloWorld
3. addNumbers
4. randoms
5. headsTails
6. post-testLoops
7. pre-testLoops
8. forLoops
9. puttingItTogether

install

1. download newest / latest python
2. download pycharm community (free) edition EDIT: or just use IDLE (offline), repl.it or trinket (online), and skip these steps
3. install both (python first), go with default settings when asked questions
4. start pycharm, create new project
5. choose location, find interpreter (where you installed python - should detect automatically)
6. add a new python file, save it and give it a name
7. try helloWorld script below, right-click run, or use run menu or shortcut key

8. any issues use ^^find Edit Configurations... button

9. ^^check if script path is correct

10. ^^check if installed Python interpreter has been selected

helloWorld

print("hello world")

Run Code

addNumbers

num1 = int(input("enter first number: "))
num2 = int(input("enter second number: "))
answer = num1 + num2
print("the answer is: " + str(answer))

Run Code

randoms

import random
print(random.randint(1,6)) #between 1 & 6 inclusive
print(random.uniform(0,1)) #between 0 & 1, floating

Run Code

headsTails

console based:

import random
if(random.randint(1,2)==1):
    print("heads")
else:
    print("tails")

Run Code

... or using a function:

import random

def flipCoinFunc():
    if(random.randint(1,2)==1):
        print("heads")
    else:
        print("tails")

flipCoinFunc()

Run Code

... or as a switch / case statement for java / C# programmers:

import random

def flipCoinFunc(x):
    return {
        1: "heads",
        2: "tails"
    }[x]

temp = random.randint(1,2)
print(flipCoinFunc(temp))

graphically:

put these images in your python folder, same location as your source file:

import random
import tkinter #for python 3, python 2 would have a capital T instead
myWindow = tkinter.Tk()
imgHeads = tkinter.PhotoImage(file="heads.gif")
imgTails = tkinter.PhotoImage(file="tails.gif")

def flipCoinFunc(event):
    if(random.randint(1,2)==1):
        resultLabel.configure(image = imgHeads)
    else:
        resultLabel.configure(image = imgTails)

btnFlip = tkinter.Button(myWindow, text="click to flip", fg="magenta")
btnFlip.bind("<ButtonPress>",flipCoinFunc)
btnFlip.pack(side="top")
resultLabel = tkinter.Label(image = imgHeads)
resultLabel.pack(side="top")
myWindow.title("my coin toss app")
myWindow.geometry("300x300")
myWindow.configure(background='salmon')
myWindow.mainloop()

post-test loops

repeats 1 or more times, not good practise!

count = 10
while True:
    print(count)
    count=count-1
    if(count < 1):
        break;
print("blastoff!")

Run Code

pre-test loops

repeats 0 or more times, use when num of iterations unknown:

count = 10
while (count >= 1):
    print(count)
    count=count-1
print("blastoff!")

Run Code

for loops

for more controlled looping, when num of iterations are known:

for look in [1,3,5,7,9]:
    print(look)

#range(start,stop,step):
for test in range(10,0,-2):
    print(test)

for x in range(1, 4): #1 to 3 only
    for y in range(1, 4):
        print(x, y)

for x in "camelCase":
    print(x)

Run Code

putting it together

simulating a "coin toss simulator", that tests how long it takes to toss consecutive heads / tails:

import random
countHeads = 0
countTails = 0
exitLoop = 7 #number of heads or tails in a row
prevFlip = 0
flip = 0
numberOfFlips = 0
 
while (countHeads < exitLoop) and (countTails < exitLoop):
          prevFlip = flip
          flip = random.randint(1,2);
          numberOfFlips += 1
          print("{face}".format(face="heads" if flip is 1 else "tails"))
          if(flip == prevFlip and flip == 1):
              countHeads+=1
          if(flip == prevFlip and flip == 2):
              countTails+=1
          if(flip != prevFlip):
              if(flip==1):
                  countHeads = 1
                  countTails = 0
              if(flip==2):
                  countHeads = 0
                  countTails = 1
print("number of flips: ", numberOfFlips)

Run Code