Variables are just boxes that you can put other things into. You can put numbers, words, other variables, and any value you can think of inside a variable. A variable is a box for stuff!
Today we will be working only with strings and ints.
Strings are words that are enclosed in either “” or ”
Ints are whole numbers
a = 2
# a is now 2
b = 3
#b is now 3
c = a + b
#c is now 5
d = a + 5
#d is now 7
a = d
#a is now 7
my_string = "a string here"
my_other_string = 'a string here'
a = '4'
b = int(a)
b == 4
a = 4
b = str(a)
b == '4'We can use variables to store things we ask our user. Our input is normally a string!
name = input("What is your name? ")
age = int(input("How old are you? "))
# You can print words
print ("This will write words out to our console")
# You can print variables
a = 5
print(a)
#The above will print 5 to our consoleprint ("A program to add up some ages")
name = input("What is your name? ")
age1 = int(input("How old are you? "))
age2 = int(input("How old is your partner? "))
print ("Between you,",name,", you are",age1+age2,"years old")We can do Math with our programs
- a+b addition
- a-b subtraction
- a*b multiplication
- a/b division (see note below)
- a//b floor division (e.g. 5//2=2)
- a%b modulo (return the remainder)
- -a negation
- abs(a) absolute value
- a**b exponent
We can test for truth in if and while statements
Remember any real value is considered True. We can also say the word True
truth = TrueAny of the following will be False:
a = None
b = False
c = 0
d = ''
We can compare values to each other with special notation
- < strictly less than
- <= less than or equal
- > strictly greater than
- >= greater than or equal
- == equal
- != not equal
a = 1
b = 2
c = a < b
# c is now True
d = a > b
# d is now False
We can combine with boolean statements:
- and
- or
- not
a = 1
b = 2
a == 1 and b == 1 # Will give us false
a == 1 or b == 1 # Will give us true
not (a == 1 or b == 1) # Will give us false
b > a and a > 0 and a != b and not b >= 5 # Will give us true
This is simply repeating things a number of times
REMEMBER COUNTING STARTS AT 0!
for i in range(3):
print(i)
#This will print
#0
#1
#2
for i in range(1,3):
print(i)
#This will print
#1
#2Remember you always have access to the variable i!
We use logic all over in our programs. We use it to compare things and make decisions with conditions.
This is where you get to make decisions and use things like comparisons boolean statements, and Truths.
test_score = 80
if test_score >= 90:
letter = 'A'
elif test_score >= 80:
letter = 'B'
elif test_score >= 70:
letter = 'C'
elif test_score >= 60:
letter = 'D'
else:
letter = 'F'
print(letter)While loops keep doing things as long as a boolean expression is True
count = 0
while (count < 9):
print ('The count is:', count)
count = count + 1Be careful of infinite loops
x = 1
while True:
print ("To infinity and beyond!", count)
x += 1
# Note the x+=1 this means that x = x+1Lists are a datatype you can use to store a collection of different pieces of information as a sequence under a single variable name.
list1 = ['a','b','c']
list2 = [3,4,5]
list3 = [] #You can have empty listsRemember lists start at 0
list1[0]will give you ‘a’
list1.index('b') will return the index of an element in this case 1
list1.append('d')This will add ‘d’ to the end of your list
You can remove elements from a list
.pop removes the element via index and returns it
list1.pop(1).remove removes the element via the actual item
list1.remove('c')You can get part of a list
list1[0:2]Given a list1=[‘a’,’b’,’c’,’d’] this will return [‘a’,’b’]
A dictionary is like a list but instead of indices we have keys and values.
my_dict = {'key1' : 1, 'key2' : 2, 'key3' : 3}
my_dict2 = {} #You can have empty dictionaries tooanimals = {'Whale' : 'mammal', 'Bear' : 'mammal', 'Burmese Python' : 'reptile'}
print animals['Whale']
This will print ‘mammal’
animals = {'Whale' : 'mammal', 'Bear' : 'mammal', 'Burmese Python' : 'reptile'}
# This is how we add an element
animals['Dog'] = 'mammal'
# Your dictionary will now look like:
{'Whale': 'mammal', 'Burmese Python': 'reptile', 'Dog': 'mammal', 'Bear': 'mammal'}
Deleting elements is easy
animals = {'Whale' : 'mammal', 'Bear' : 'mammal', 'Burmese Python' : 'reptile'}
# This is how we delete an element
del animals['Whale]
# Your dictionary will now look like:
{'Burmese Python': 'reptile', 'Bear': 'mammal'}
A function is giving a block of code a name so that you can reuse it or simply make your program more organized.
def my_function():
print ("Hello")
my_function()def print_my_argument(words):
print(words)
my_argument = "Hello World"
print_my_argument(my_argument)def add_two_numbers(num1,num2):
sum = num1 + num2
return sum
mysum = add_two_numbers(4,4)
mysum == 8Hint: Variables and Input and Output are all you need
Example output:
What is your favorite animal? Dog
My favorite animal is the Dog too!
Hint: You can ask for multiple variables and use them multiple times. Have fun writing whatever you like with as many blanks as you would like.
Example output:
Give me a noun: monkey
Give me a verb: fly
Give me a noun: koala
When you are programming make sure you bring your monkey and your wits. They will serve you well as you fly the koala.
Hint: You just need input/output, variables, and some math. The formula for the area of a rectangle is A = Length X Width
Example output:
What is the length?: 5
What is the width?: 9000
The area is 45000!
Hint: Use for loops and print()
Example output:
1
2
3
4..
100
Hint: Use for loops, math, and print()
Example output:
1
4
9
16
25…
2500
Hint: You can loop through a string
Example output: What is your name?London
L
o
n
d
o
n
Hint: All you need is input/output, variables, and some basic math! 1 ft = 12 in.
Example output:
How many feet? 12
That is 144 inches!
Awesome Bonus Extravaganza Challenge: Give your program your height in feet and inches. Have it tell you your actual height in inches.
Hint: the formula for area is A = pi*r^2, the formula for circumference is C = 2*pi*r
Hint 2: At the top of your file you can add “from math import pi” and then you can use pi like a variable. What is happening here? Or you can just use 3.14!
Example output:
What is the radius of the circle? 5
Your circumference is 31.41592653589793
Your area is 78.53981633974483
Hint: You can use variables as your range variable
Example output:
How many times would you like to loop?:2
This is loop 0
This is loop 1
LOOPS ARE AWESOME!
Challenge 9: Take any Number and Print a Times Tables to Twelve - Or Have Your Computer Do Your Homework
Hint: Use a for loop and some simple math
Example ouput:
What would you like to multiply?:11
11
22
33
44
55
66
77
88
99
110
121
132
Take in a number and add up each number as you count to that number Fun Fact: This is called a Gaussian Sum. That’s calculus!
Example output:
What is your number?:22
253
AMAZING BONUS GOODWORK CHALLENGE: Have your program show your work
Example output:
What is your first number? 4
What is your second number? 5
5 is larger than 4
Create a simple calculator that can add, subtract, multiply, and divide two numbers.
Example output:
What would you like to do(add,subtract,divide, or multiply)? multiply
What is your first number? 20
What is your second number? 10
2000
Create a program that counts to 100.
If the number is divisible by 3 print Fizz
If the number is divisible by 5 print Buzz
If the number is divisible by 3 and 5 print FizzBuzz
If the number is none of the above print the number
Hint: use the % math operator - it gives you the remainder
Example output:
1
2
Fizz
4
Buzz
Fizz
7
8
Fizz
Buzz
11
Fizz
13
14
FizzBuzz
16
17
Fizz
19
Buzz
Fizz…
Buzz
Hint: you can loop through a string
mystring = 'hello'
for i in mystring:
print(i)
#This program will output:
# h
# e
# l
# l
# oExample output:
What word would you like to count the vowels for? orange
orange has 3 vowels
Write a program that converts from Celsius to Fahrenheit and Fahrenheit to Celsius
Hint: Temp Fahrenheit = Temp Celsius * 9/5 + 32
Hint 2: Temp Celsius = (Temp Fahrenheit - 32) * 5/9
Example output:
Would you like to convert Celsius to Fahrenheit (enter c) or Fahrenheit to Celsius (enter f)? f
What is the temperature in Fahrenheit? 32
That is 0 Celsius
Ask how many numbers the user would like to average, get the numbers and give the average.
Hint: Use a while loop
Example output:
How many numbers would you like to average? 5
What is number 1? 20
What is number 2? 40
What is number 3? 50
What is number 4? 60
What is number 5? 50
The average of those 5 numbers is 44
Have the computer think of a number. You try to guess the number as the computer gives you hints. Quit when you guess the number and print the number of tries.
Hint 1: We can get a random number by doing the following
import random
secret_number = random.randint(0,100)
# this will give us a random integer between 0-100Hint 2: Use a while loop
Example output:
I’m thinking of a number between 0 and 100 what do you think it is? 5
Nope higher than 5, guess again: 90
Nope lower than 90, guess again: 80
Nope higher than 80, guess again: 85
Nope higher 85, guess again: 89
You got it! It only took you 5 guesses. Thanks for playing!
Make a function that prints each letter of the alphabet on a new line
Example output: a
b
c
d…
z
It’s Ralph’s and Rachel’s birthday. Write a function that takes a single name as an argument and “sing” happy birthday.
Sing happy birthday to Ralph and Rachel
Example output:
Happy Birthday to you!
Happy Birthday to you!
Happy Birthday, dear Ralph
Happy Birthday to you!
Happy Birthday to you!
Happy Birthday to you!
Happy Birthday, dear Rachel
Happy Birthday to you!
Make a function that takes a name, age, weight, and height and prints a bio.
Example output:
Tell me your name: Joe
Tell me your age: 12
Tell me your weight (in pounds): 100
Tell me your height (in inches): 50
Joe is 12 and weighs 100 pounds and is 50 inches tall.
The International Civil Aviation Organization (ICAO) alphabet assigns code words to the letters of the English alphabet acrophonically (Alfa for A, Bravo for B, etc.) so that critical combinations of letters (and numbers) can be pronounced and understood by those who transmit and receive voice messages by radio or telephone regardless of their native language, especially when the safety of navigation or persons is essential.
Write a program that takes a string and returns the ICAO equivalent.
Here is a dictionary of all the equivalents:
d = {'a':'alfa', 'b':'bravo', 'c':'charlie', 'd':'delta', 'e':'echo', 'f':'foxtrot',
'g':'golf', 'h':'hotel', 'i':'india', 'j':'juliett', 'k':'kilo', 'l':'lima',
'm':'mike', 'n':'november', 'o':'oscar', 'p':'papa', 'q':'quebec', 'r':'romeo',
's':'sierra', 't':'tango', 'u':'uniform', 'v':'victor', 'w':'whiskey',
'x':'x-ray', 'y':'yankee', 'z':'zulu'}Example output:
What is your string? Fun
Foxtrot Uniform November
Write a function char_freq() that takes a string and builds a frequency listing of the characters contained in it. Represent the frequency listing as a Python dictionary.
Example output:
What is your string? abbabd
{‘a’: 2, ‘b’: 3, ‘d’: 1}
Take a list of integers and return a simple visual histogram
Example output:
Given a list of [3,4,6]
Ouput
***
****
******
Write a function which takes a list of words and tells us which is the longest
Example output:
Given a list [‘word’,’blue’,’yellow’]
yellow is the longest word!
- Sort numbers
- Determine palindrome
- Factorial
- Hanoi