# Every program has the ability to perform actions on a list of

# values. The for loop can be used to do this.

# Each time we go through the loop variable i's value will be

# assigned the next value in our list

for i in [2,4,6,8,10]:

print("i = ", i)

# We can also have range define our list for us. range(10) will

# create a list starting at 0 and go up to but not include

# the value passed to it.

for i in range(10):

print("i = ", i)

# We can define the starting and ending value for range

for i in range(2, 10):

print("i = ", i)

# You can use modulus to see if a number is odd or even

# If we divide an even by 2 there will be no remainder

# so if i % 2 == 0 we know it is true

i = 2

print((i % 2) == 0)

# ---------- PROBLEM : PRINT ODDS FROM 1 to 20 ----------

# Use a for loop, range, if and modulus to print out the odds

# Use for to loop through the list from 1 to 21

for i in range(1, 21):

# Use modulus to check that the result is NOT EQUAL to 0

# Print the odds

if ((i % 2) != 0):

print("i = ", i)

# ---------- WORKING WITH FLOATS ----------

# Floating point numbers are numbers with decimal values

your_float = input("Enter a float: ")

# We can convert a string into a float like this

your_float = float(your_float)

# We can define how many decimals are printed being 2

# here by putting :.2 before f

print("Rounded to 2 decimals : {:.2f}".format(your_float))

# ---------- PROBLEM : COMPOUNDING INTEREST ----------

# Have the user enter their investment amount and expected interest

# Each year their investment will increase by their investment +

# their investment * the interest rate

# Print out their earnings after a 10 year period

# Ask for money invested + the interest rate

money = input("How much to invest: ")

interest_rate = input("Interest Rate: ")

# Convert value to a float

money = float(money)

# Convert value to a float and round the percentage rate by 2 digits

interest_rate = float(interest_rate) * .01

# Cycle through 10 years using for and range from 0 to 9

for i in range(10):

# Add the current money in the account + interest earned that year

money = money + (money * interest_rate)

# Output the results

print("Investment after 10 years: {:.2f}".format(money))

# ---------- WORKING WITH FLOATS ----------

# When working with floats understand that they are not precise

# This should print 0 but it doesn't

i = 0.1 + 0.1 + 0.1 - 0.3

print(i)

# Floats will print nonsense beyond 16 digits of precision

i = .11111111111111111111111111111111

j = .00000000000000010000000000000001

print("Answer : {:.32}".format(i + j))

# ---------- ORDER OF OPERATIONS ----------

# When making calculations unless you use parentheses * and /

# will supersede + and -

print("3 + 4 * 5 = {}".format(3 + 4 * 5))

print("(3 + 4) * 5 = {}".format((3 + 4) * 5))

# ---------- THE WHILE LOOP ----------

# We can also continue looping as long as a condition is true

# with a while loop

# While loops are used when you don't know how many times

# you will have to loop

# We can use the random module to generate random numbers

import random

# Generate a random integer between 1 and 50

rand_num = random.randrange(1, 51)

# The value we increment in the while loop is defined before the loop

i = 1

# Define the condition that while true we will continue looping

while (i != rand_num):

# You must increment your iterator inside the while loop

i += 1

# Outside of the while loop when we stop adding whitespace

print("The random value is : ", rand_num)

# ---------- BREAK AND CONTINUE ----------

# Continue stops executing the code that remains in the loop and

# jumps back to the top

# Break jumps completely out of the loop

i = 1

while i <= 20:

# If a number is even don't print it

if (i % 2) == 0:

i += 1

continue

# If i equals 15 stop looping

if i == 15:

break

# Print the odds

print("Odd : ", i)

# Increment i

i += 1

# ---------- PROBLEM : DRAW A PINE TREE ----------

# For this problem I want you to draw a pine tree after asking the user

# for the number of rows. Here is the sample program

'''

How tall is the tree : 5

#

###

#####

#######

#########

#

'''

# You should use a while loop and 3 for loops

# I know that this is the number of spaces and hashes for the tree

# 4 - 1

# 3 - 3

# 2 - 5

# 1 - 7

# 0 - 9

# Spaces before stump = Spaces before top

# So I need to

# 1. Decrement spaces by one each time through the loop

# 2. Increment the hashes by 2 each time through the loop

# 3. Save spaces to the stump by calculating tree height - 1

# 4. Decrement from tree height until it equals 0

# 5. Print spaces and then hashes for each row

# 6. Print stump spaces and then 1 hash

# Get the number of rows for the tree

tree_height = input("How tall is the tree : ")

# Convert into an integer

tree_height = int(tree_height)

# Get the starting spaces for the top of the tree

spaces = tree_height - 1

# There is one hash to start that will be incremented

hashes = 1

# Save stump spaces til later

stump_spaces = tree_height - 1

# Makes sure the right number of rows are printed

while tree_height != 0:

# Print the spaces

# end="" means a newline won't be added

for i in range(spaces):

print(' ', end="")

# Print the hashes

for i in range(hashes):

print('#', end="")

# Newline after each row is printed

print()

# I know from research that spaces is decremented by 1 each time

spaces -= 1

# I know from research that hashes is incremented by 2 each time

hashes += 2

# Decrement tree height each time to jump out of loop

tree_height -= 1

# Print the spaces before the stump and then a hash

for i in range(stump_spaces):

print(' ', end="")

print("#")