Cheatography

# Python Cheat Sheet Cheat Sheet by primmito

Python Sheet

### Counting Down

 ``````while True:     user_number = input ("Enter a number")     number = int (user_number)     countdown_string = ""     while number > 0:         countdown_string = countdown_string + str(number)         number = number - 1              print (countdown_string)``````

### Area of Triangle

 ``````#write a function #name: areaofTriangle #parameter: base height #return: area def areaofTriangle (base, height):     return 1/2baseheight user_base= float(input("Enter the base of the triangle: ")) user_height= float(input("Enter the height of the triangle: ")) #function call print ("The area of the triangle is", areaofTriangle (user_base, user_height))``````

### Returning largest value

 ``````#write a function that returns the largest of two values # name: max2 # arguments: num1, num2 #return: the largest value def max2 (num1, num2):     maxvalue = num1     if num2 > maxvalue:      maxvalue = num2     return maxvalue print (max2 (2,3)) print (max2 (2,99)) print (max2 (2,55)) #write a function that returns the largest of three values # name: max3 # arguments: num1, num2, num3 #return: the largest value``````

### Vocabulary

 Variables a value that can change, depending on conditions or on inform­ation passed to the program. String list of charac­ters, symbols and could also have numbers. Syntax structure of a program. Print to display a value on the screen Loop when the instru­ctions repeat over and over. Integer Number Whole number/ counting number Float Number The number in decimal Modulo Used to finds the remainder Boolean True/False List Writing consec­utive words, numbers down, one below the other in [] Algorithm A list of steps to finish something. Instru­ctions that can be performed with or without a computer. Code Commands created to allow computer to perform the functions.

 string + string Combines that strings together (squished together) string + number Crash! number + number Addition (Math)

### Random List

 ``````import random intlist = [1,2,3,4,5] random_int = random.choice(intlist) print (intlist, random_int) fplist = [1.0,2.0,3.0,4.0,5.0] random_fp = random.choice (fplist) print (fplist, random_fp) strlist = ["candy", "marshmellow", "icecream", "lollipop"] random_str = random.choice (strlist) print (strlist, random_str) mylist =[1,2,3, 5.0,6.0,7.0, "Candy", "Icecream", "Gummybears"] random_item = random.choice (mylist) print (mylist, random_item) myvar1 = 1 myvar2 = 2 myvar3 = 3 varlist = [myvar1, myvar2, myvar3] random_var = random.choice (varlist) print (varlist, random_var)``````

### Countdown Machine

 ``````user_number = input("What number do you want to count down?") number = int(user_number) countdown_string = ' ' while number > 0: countdown_number =countdown_string + str(number) + " " number = number -1 #print(number) print (countdown_string)``````

### Receives number from user. State if Neg,Po­s,Zero

 ``````while True:     user_input = input ("Enter a number: ")     user_input = int(user_input)     if user_input > 0:         print (user_input, "is positive.")     elif user_input < 0:         print (user_input, "is negative.")     elif user_input == 0:         print (user_input, "is zero.")``````

### Area of Circle

 ``````def areaOfCircle (r): #r=radius     pi = 3.1415     area = pi r *2     return area user_radius = input ("Enter the radius:") radius = float(user_radius) print ("The area of the circle is", areaOfCircle(radius))``````

### mylist, print all item using loop

 ``````mylist = [1,2,3] for item in mylist:     print (item)``````

### F

 `````` def myprint (text): #text is (something your giving to the function) an argument (parameter) to the function     print ("" + str(text) + "")     return #This exits the function myprint(1) myprint(2.5) myprint ("hello") def myprint2 (text, decoration):     print (decoration + text + decoration)     return myprint2 ("hello", "+++") myprint2 ("hello", "_=_=_=") myprint2 ("hello", ">>>>>>") def double (number):     return number * 2 #return value print(double(2)) myvar = double(double(3)) #same as double (6) because double(3) == 6 print(myvar)``````

 ``````user_input = input("Enter a number:") user_input = int (user_input) print (user_input*5)``````

### Output

 ``````x = false print (x and True or 1 ==1) #OUTPUT = TRUE``````

### returning largest value continue

 ``````def max3 (num1, num2, num3):     maxvalue = num1          if maxvalue < num2:         maxvalue = num2     if maxvalue < num3:         maxvalue = num3     return maxvalue print (max3 (8,4,3)) #write a function that returns the largest number in the list #name : maxlist #argument: list #return: the largest value in the list``````

### Function

 float() Change number to be decimal number. print() Show inform­ation that you want on the screen. int() Change the number­/string into a integer. str() A list of number, letter and symbols. input() Gain inform­ation from user. len() The length of the string

### Multip­lic­ation and Exponents

 string * number Combines that string in the amount of numbers. string *string Crash! number * number Multiple (Math) string **string Crash! number ** number Exponent (Math) string ** number Crash!

### Print all even numbers from -100 to -1. While loop

 ``````mynum = -100 while mynum <-1:     print (mynum)     mynum= mynum + 2``````

### Function

 ``````#how to create a function 1 def NameofFunction (myvar1, myvar2):     print ("hello")     return myvar1, myvar2 #function call NameofFunction (2, 3) #Code above, prints only hello #2 def NameofFunction (myvar1, myvar2):     print ("hello")     return myvar1 + myvar2 #function call NameofFunction (2, 3) myanswer = NameofFunction (4,1) print (myanswer) #code 2 prints out hello hello and 5``````

### Operations

 ``````def sum(a,b):     return a + b def product (a,b):     return a * b def diff (a,b):     return a - b def div (a,b):     if b != 0:         return a // b     else:         print ("Error") def calc(num1, num2, operation):     if operation == "sum":         return sum (num1, num2)     elif operation == "product":         return product (num1, num2)     elif operation == "diff":         return diff (num1, num2)     elif operation == "div":         return div (num1,num2)      print (calc(1,2, "sum")) print (calc(4,2, "diff")) print (calc(10,0, "div")) print (calc(2,12, "product"))``````

### Volume Of Prism

 ``````#Write the function compute volume of prism #name: volumerOfPrism #Parameter: base, height, prism_height #return volume def volumeOfPrism (base, height, prism_height):     #area * prism_height     volume = areaOfTriangle (base,height)* prism_height     return volume user_prism_height = float(input("Enter the prism height: ")) print ("The volume of the prism is", volumeOfPrism (user_base, user_height, user_prism_height))``````

### returning largest value continue2

 ``````def maxlist (list):     maxvalue =(list)     for item in list:         if maxvalue < item:             maxvalue = item     return maxvalue print (maxlist(range(0,123)))``````

### Naming Convention

 ``````Rules for giving names - letters - numbers (Can't be the first letter) - underscore _ Valid - _mystr - my3 - Hello_there Invalid name - 3my="hi" -- cannot start with number -firstname ="hi" = first-name``````

### Examples

 ``````print (2) - integer print (2.5) - floating point print ("Hello") - string print (mystr) - variable print (mystr, "hi", 2,1,0) - - commas mystr = "Hi" mystr - name "Hi" - value can change print (int(1.5)) - 1 print (int ("2") - 2 print (float (1)) - 1.0 anything to a float``````

### Reverse Word

 ``````while True:     word = input("Please enter a word: ")     index = 0     reverse = ''     while index < len(word):         reverse = word[index] + reverse         index = index + 1         print ("Reverse ", reverse)``````