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Cheatography

Python Cheat Sheet by

Symbol

float()
number with decimal point
str()
string
int()
integer
len()
the length of the word or string

Multiply

string * number
Repeat those thing for the number of time
string * string
Crash!
number * number
Multiply like in math

Exponents

string ** number
Crash!
number ** number
Exponent in Math
number ** string
Crash!

Rule for naming the variable

Rule for naming variab­­les
# letters
# numbers
# underscore (_)
# can either start with letter or under­­scores ONLY
# no space
Exam­­ple
Hello_­­there
me2
_mynumber
Invalid names
# 3my =cannot start with number
# last name = no spaces allowed
# last­-­­­name = dashes are not accepted

Define Function

varl = 1
_varl = 3
_varl + 100

print(_varl)

def bacon(): # defines a functio named bacon
    print ("hello it's bacon")
    print ("line2")
    print ("line3")
    print ("line4")
    print ("line5")
    print ("line6")
    print ("line7")
    return #exit the fuction

bacon()
bacon()
bacon()

def myprint (text):
    print ("***"+ str(text) +"***")
    return

myprint(1)
myprint("hello")
myprint(2.5)

def myprintnew (text, decoration):
    print (decoration + str(text) + decoration)
    return

myprintnew (1,"+++")
myprintnew ('hello','-=-=-=-=-=-=-=-=')
myprintnew (1,"@@@@@@@")

def doubleit(number):
    return number * 2

print (doubleit(3))

print (doubleit(doubleit(4)))
myvar = 12
myvar = doubleit(myvar)
myvar = doubleit(myvar)
print(myvar)
Result
3
hello it's bacon
line2
line3
line4
line5
line6
line7
hello it's bacon
line2
line3
line4
line5
line6
line7
hello it's bacon
line2
line3
line4
line5
line6
line7
1
hello
2.5
+++1+++
-=-=-=-=-=-=-=-=hello-=-=-=-=-=-=-=-=
@@@@@@@1@@@@@@@
6
16
48

Example

firstname = input("What is your fisrt name?")
lastname = input("What is your last name?")

fullname = firstname + " " + lastname
print(fullname)

letternumber = input("What is the letter of number?")

letternumber = int(letternumber)

if letternumber>len(fullname):
    print("Invalid letter number, try again")
else:
    print(fullname[letternumber])

    times = input("How many times to print the letter?")
    times = int(times)

    if times>100:
        print("Too many letters to print")
    else:
        print(fullname[letternumber]*times)
Result
What is your fisrt name? Pear
What is your last name? Tan
 Pear Tan
What is the letter of number? 4
r
How many times to print the letter? 12
rrrrrrrrrrrr

Example

mystr = "hello123"

numbers = [1,2,3,4,5,6]
print (numbers)

shoppinglist = ['shoes','bags','pants','shirts']
print (shoppinglist)

mixed = [1, 'hello', 2.5, True, False]
print (mixed)


letter_num = 0

while letter_num < len(mystr):
    print (mystr[letter_num])
    letter_num = letter_num + 1

for myletterisawesome in mystr:
    print(myletterisawesome)

for tientien in shoppinglist:
    print(tiemtiem)

out = 0

for mrtim in shoppinglist:
    out = out + 1
Result
[1, 2, 3, 4, 5, 6]
['shoe', 'bags', 'pants', 'shirt']
[1, 'Hello', 2.5, True, False]

word per line

mystr = input(" Please enter your word")

letter_num = 0

while letter_num < len(mystr):
    print (mystr[letter_num])
    letter_num = letter_num + 1
Result
Please enter your word1,2,3,
1
,
2
,
3
,

The area of circle

while True:
    user_radius = input("Enter the radius of the circles")

    radius = float(user_radius)

    pi = 3.1415

    #
    answer = pi * (radius**2)

    print("The area of the circle is",answer)
Result
Enter the radius of the circles3
The area of the circle is 28.273500000000002

Palindrome

word = input("Please enter a string: ")
letter_num = 0

reverse = ""

while letter_num <len(word):
    reverse = word[letter_num] + reverse
    letter_num = letter_num + 1
if word == reverse:
    print("It is palindrome")
else:
    print("It is not palindrome")

Group work

"""
Group Members: Earn, Pop, Pear

Class: 1005
"""
import random

# create a list

mylist = ['earn', 'pear', 'pop', 'jaja', 'roong']

random_item = random.choice(mylist)


#print
print("mylist:",mylist)

# ask the user to input the word

chance = 5
score = 0


while chance!= 0:
    user_guess = input("Guess a word: ")
    
    if user_guess == random_item:
        score = score + 100
        print("That's correct!","Score",score)
        random_item = random.choice(mylist)
       
    else:
        chance = chance - 1
        print("Chances Remaining:",chance)
       
        #check if that word is in the list
        if user_guess in mylist:
             print ("Sorry, wrong choice")
        else:
             print("Sorry, that is not even in the list!")

if chance == 0:
    print(random_item)
    print("Final score:",score)
Result
mylist: ['earn', 'pear', 'pop', 'jaja', 'roong']
Guess a word: pear
Chances Remaining: 4
Sorry, wrong choice
Guess a word: earn
Chances Remaining: 3
Sorry, wrong choice
Guess a word: pop
Chances Remaining: 2
Sorry, wrong choice
Guess a word: jaja
Chances Remaining: 1
Sorry, wrong choice
Guess a word: roong
That's correct! Score 100
Guess a word: jaja
Chances Remaining: 0
Sorry, wrong choice
pear
Final score: 100
 

Function

input()
inform­ation that receive from user
print()
show inform­ation in the screen

Addition or Plus

string + string
combine those strings together
string + number
program will be crash
number + number
add together like doing math

Symbol

+
plus or add
-
subtract
*
multiply
**
exponent
/
divide and quotient (result) is float
//
divide and quotient (result) is integer
%
remainder (modulo)
==
equal to
!=
not equal to
<=
less than or eqaul to
<
less than
>
more than
>=
more than or equal to
#
one line comment that will not included in the code
"­"­"
Multi-line comment
True or anything
Always true
False and anything
False

The area of circle 2

def areaOfCircle (user_radius):

    if user_radius<=0:
        return "Error: invalid radius"
    
    pi = 3.1415
    area = pi*(user_radius**2)
    return area
user_radius = float(input("Enter the radius: "))
print('The area of the circle is', areaOfCircle(user_radius)

Enter the radius: 3
The area of the circle is 28.273500000000002

Meaning of the word

def printDefinition(word):
    # write a definition in your own words for the folllowing words:
    # use multi-line strings to print the definition
    #variable
    if word == "variable":
        print("""

        A variable is thing that can be changed

        """)
    elif word == "function":

        #function
        print ("""

        A function is a thing that reuse block or quote.

        """)
    elif word == "parameter":

        #parameter
        print("""

        A parameter is thing inside blacket of function

        """)
    elif word == "agument":

        #argument
        print("""

        A argument is the same thing as parameter. It is thinfg inside blacket f function

        """)
    elif word == "function call":
        #function call
        print("""

        Function is the thing make fuction run.

        """)
    elif word == "string":

        #string
        print("""

        A string is a list of character

        """)
    else:
        print("unknown word")
while True:
    word = input ("Enter the word")
    printDefinition(word)

Result
Enter the wordvariable
       
 A variable is thing that can be changed
        
Enter the wordfunction

 A function is a thing that reuse block or quote.
        
Enter the wordagument

 A argument is the same thing as parameter. It is thinfg inside blacket f function
       
Enter the wordfunction call

Function is the thing make fuction run.
        
Enter the wordstring
A string is a list of character
       
Enter the wordpear
unknown word

Count down

user_number = input("What is the number?" )

number = int(user_number)
countdown_string =''

while number > 0:
    countdown_string = countdown_string + str(number)
    number = number-1

print(countdown_string)

Result
What is the number? 5
54321

List

import random

# Create a list of integers
intlist = [1,2,3,4]
random_int = random.choice(intlist)
print(intlist,random_int)#print the entire list and the random item


# Create a list of floating point numbers
fplist=[1.1,2.2,3.3,4.4]
random_fp = random.choice(fplist)
print(fplist,random_fp)

# Create a list of strings
strlist=['phone','pencil','computer']
random_str = random.choice(strlist)
print(strlist,random_str)

mylist = [1,2,3,4,1.1,2.2,3.3,4.4,'phone','pencil','computer']
random_item = random.choice(mylist)
print(mylist,random_item)

#create a list of follwing veraibles
myvar1 = 1
myvar2 = 2
myvar3 = 3
varlist = [myvar1,myvar2,myvar3]
random_var = random.choice(varlist)
print(varlist,random_var)
Result
[1, 2, 3, 4] 3
[1.1, 2.2, 3.3, 4.4] 3.3
['phone', 'pencil', 'computer'] phone
[1, 2, 3, 4, 1.1, 2.2, 3.3, 4.4, 'phone', 'pencil', 'computer'] pencil
[1, 2, 3] 2

Guess game with random

import random

# create a list

mylist = ['lion','cheetah','panther','cougar','leopard']

random_item = random.choice(mylist)
print(random_item)

#print
print(mylist[0])

# ask the user to input the word
user_guess = input("Guess a word: ")

if user_guess == random_item:
    print("Correct")
else:
    
    #check if that word is in the list
    if user_guess in mylist:
        print("Yes, it is in the list")
    else:
        print("No, it is not in the list")

List

myself= "hello123"

numbers = [1,2,3,4,5,6]
print(numbers)

shoppinglist = ['shoe','bags','pants','shirt']
print(shoppinglist)

mixed=[1,'Hello',2.5, True, False]
print(mixed)

letter_num = 0

while letter_num < len(mystr):
    print (mystr[letter_num])
    letter_num = letter_num + 1

for myletterisawesome in mystr:
    print(myletterisawesome)

for tientien in shoppinglist:
    print(opal)
shoppinglist. append('ties')
print(shoppinglist)


out = 0

for mrtim in shoppinglist:
    out=out + 1
    print(mrtim)
print (out)

largelist = range(100)

for num in largelist:
    print(num)

Decision making

f 3 < 2: #if statement must compare two Booleans
   print ('3 is less than2 ')
elif 4 < 2: #can have 0 or more elif statements
    print ('4 is less than 2')
elif 5 < 2:
    print ('5 is less than 2')
else: #can have 0 or 1 else statement at the end
    print ('none of the above are True')

Function

def nameOfFunction():
     print (‘This function has no parameters’)
     print (‘This function has no return value’)
     return # no value, just exits the function

#function call
nameOfFunction()

#function with 1 parameter/argument
def testFunction(param):
print (‘This function has 1 parameter’)
print (param)

#function call
testFunction (“this is the parameter value”)

#function with 2 parameters and a return value
def function3(param1, param2):
      print(‘This function has 2 parameters’)
      return param1 + param2 # return value

#function call and store the result in a variable
returnValue = function3(2, 3)
print (returnValue)

Determine zero positive and negative

num = int (input("Enter a number")
if num>0:
    print (num,"is positive")
elif num<0:
    print (num,"is negative")
else:
    print (num,"is zero")

Divisible by 3

num = int(input(" Enter a word"))
remainder = num%3
if remainder ==o:
   print(num,"is divisible by 3")
else:
   print(num,"is not divisible by 3")

Fibonacci fron o to 50

num1 = 0
num2 = 0
fibonacci = num1+num2
myoutput = "0,1"
while fibonacci < 50:
          myoutput = myouput + "," + str(fibonacci)
          num1=num2
          num2 = fibonacci
          fibonacci = num1+ num2
print(my output)
0,1,1,2,3,5,8,13,...

Sample

def test() :
    while True:
     user_input = input("Please enter a word: ")
     if user_input == 'quit':
         break

    return
test()
 keep asking word till input quit
 

Vocabulary

variable
A value or thing that can be changed
string
A list of character such as letter or symbol
boolean
True False
modulo
Find the remainder
syntax
There are error such as grammar or structure of language
float
A number with decimal point
integer
Rounded number which do not have decimal point

Condition

while...
While this is true loop the command under the condit­­ional
while True
Forever loop
for each item in name of list
For every item in the list repeat the command under the loop that many times. (a string is a list too)
If...: then... else
If the statement in 'if ' is true, it will follow the statement in 'then'. If it is not, it will follow statement under 'else'.

The largest value

#write a function that returns the largest of two values
#name : max2
#agruments: num1, num2
# return: largest value

# write a functrion that returns the largest of three values
# name : max3
#agrument: num1, num2, num3
# return: largest value

def max2(num1,num2):
    if num1 >= num2:
        max_value = (num1)
    if num2 > num1:
        max_value = (num2)
    return max_value

num1 = input('Enter the the first value')
num2 = input('Enter the the second value')
print (max2(num1,num2))

def max3(num1,num2,num3):
    if num1 >= num2 and num1 >= num3:
        max_value = (num1)
    if num2 > num1 and num2 >= num3:
        max_value = (num2)
    if num3 >= num2 and num3 >= num1:
        max_value = (num3)
        
    return max_value

num3 = input('Enter the the third value')
print (max3(num1,num2,num3))

# write a function that returns the largest value
# name: maxlist
#argument : list
#returns the largest value in the list

def maxlist(list):
    maxvalue = list(0)

    for item in list:
        if item > maxvalue:
            value = item
        
    return maxvalue

mylist = [1,2,3,4,55,66,777,0,1]
print (maxlist(list))

Area of Triangle & Volume of prism

# write a function that computes the area of triangle

# name : areaOfTriangle
# parameters :b,h
# return : area

def areaOfTriangle(b,h):
    if user_base<=0:
        return "Error: invalid radius"
    if user_height<=0:
        return "Error: invalid radius"
    area = 0.5 b h
    return area


user_base =float(input('Enter the base of the triangle:'))
user_height = float(input('Enter the height of the triangle: '))
print ('The area of the triangle is',areaOfTriangle(user_base,user_height))

#write a function that computes the volume of a prism
# name: volumeOfPrism
# parameters :b,h,l
# return : volume

def volumeOfPrism(b,h,l):
    volume = bhl
    return volume
user_length = float(input('Enter the length of the prism:'))

print('The volume of the prism is', volumeOfPrism(user_base,user_height,user_length))


Result
Enter the base of the triangle:12
Enter the height of the triangle: 6
The area of the triangle is 36.0
Enter the length of the prism:3
The volume of the prism is 216.0

Useful Function for Name

mystr = "hello THERE"

print (mystr.upper()) > HELLO THERE
print (mystr.lower()) > hello there
print (mystr.capitalize()) > Hello there
print (mystr.title()) > Hello There

How to convert to binary

user_number = input("Please enter a number")

number = int(user_number)

binary_string =''
while (number > 0):
    remainder= number%2
    binary_string = str(remainder) + binary_string
    number= number//2
    

print("Binary string is", binary_string)
Result
Please enter a number 36
Binary string is 100100

Guess a word

# create a list

mylist = ['lion','cheetah','panther','cougar','leopard']

#print
print(mylist[0])

# ask the user to input the word
user_guess = input("Guess a word: ")

#check if that word is in the list
if user_guess in mylist:
    print("Yes, it is in the list")
else:
    print("No, it is not in the list")

Boolean

print(True)
print (2<3)
print (2 != 2)

Reverse

word = input("Please enter a word to reverse: ")

letter_num = 0

reverse = ""

while letter_num <len(word):
     reverse = word[letter_num] + reverse
     letter_num = letter_num + 1


print("Reverse: ",reverse)
Result
Please enter a word to reverse: 0123456
Reverse: 6543210

Range

#creates a list of numbers from 0 to the specified
number
numberlist = range(5)
# is the same as creating the following list
numberlist2 = [0, 1, 2, 3, 4]
for num in range(100):
     print (num) # prints all numbers from 0 – 99
for num in range(5, 50):
      print(num) #prints all numbers from 5 - 49

For loop with list

forlist = [3, 4, 5, 2, 1]
for item in forlist:
      print(item)

print all items in the list

While Loop with List:

thelist = [4, 3, 2, 1, 0]
index = 0 # start at the first item
while index < len(thelist):
         print (thelist[index]) #prints each item
         index = index + 1

Lists

mylist = [2,3,4,5] # create a list

#select an item from a list
print (mylist[0]) #selects first item and displays 2

# len() determines the length of the list
print (len(mylist)) # displays 4

mylist.append(5) # adds an item to the end of the list

Condition while loop

count = 0 # start at zero
while count < 10: # loop while count is less than 10
          print(count) #will print numbers 0 - 9
          count = count + 1 # must increase count

palindrome

def palindrome(word):
    letter_num = 0
    reverse = ""
    for letter_num in word:
         reverse = letter_num + reverse

    if word == reverse:
        return True
    else:
        return False

while True:
    user_word = input("Please enter a word: ")
    if user_word != "quit":
        print("This word has",len(user_word),"letters")
    if user_word == "quit":
         break
    if palindrome(user_word) == True:
        print(user_word,"is palindrome")
    else:
        print(user_word,"is not palindrome")
Result
Please enter a word: 321
This word has 3 letters
321 is not palindrome
Please enter a word: 212
This word has 3 letters
212 is palindrome
Please enter a word: quit

while loop with counting number

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

num = 0
while num< 100:
     num = num + 2
     print(num)

Example from sheet

mystring = " "
count = 0
while count < 5:
      mystring = mystring+ str(count)
      print (mystring)
      count = count + 1

mystring = " "
for num in range(5):
      mystring = mystring+ str(count)
      print (mystring)g
Result
0
01
012
0123
01234

Positive integer count

evencount = 0
oddcount = 0
while True:
         num = int (input("Enter a positive integer"))
         if num < 0:
                  print ("Even numbers:",evencount)
                  print ("Odd numbers:",odd count)
                  break
         else:
                  if (num%2) == 0:
                      evencount = evencount + 1
                  else:
                        oddcount = oddcount + 1

program that repeatedly recieve positive integers from the user. When the user enters a negative integer, exit the loop and print how many of the numbers were odd and even
 

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