# EXAMPLE 1 --- A list of all numbers 0-19
# long form... too much code, ugh!
numbersV2 = []
for x in range(0,20):
numbersV2.append(x)
print("V2: ", numbersV2)
numbersV1 = [ x for x in range(0,20) ]
print("V1: ", numbersV1)
# list comprehensions - a shorthand way to create a list
a = ['1','2','3','4','5','6','7']
print("a: ", a)
b = [ int(x) for x in a ]
print("b: ", b)
# EXAMPLE 2 --- A list of even numbers 0-18
# long form... SO MUCH CODE! :(
evenNumbersV2 = []
for num in range(0,20):
if num % 2 == 0:
evenNumbersV2.append(num)
print("V2:", evenNumbersV2)
# we can even use if statements in list comprehension
evenNumbersV1 = [num for num in range(0,20) if num % 2 == 0]
#evenNumbersV1 = [num for num in range(0,20,2)]
print("V1:", evenNumbersV1)
# EXAMPLE 3 -- Loops
# for loop which loops 10 times
print("for loops:")
for number in range(0,10):
print(number)
# while loop which loops 10 times
print("while loops:")
myNumber = 0
while (myNumber < 10):
print(myNumber)
myNumber = myNumber + 1
# EXAMPLE 4 -- why while loops are useful
# * any for loop can be written as a while loop,
# but not all while loops can be written as for loops!!
# * important: we don't have to know how many times the while loop will execute
# * here, we keep asking the person to enter in usernames & passwords. we only
# stop asking once they enter in a value "X" to stop.
givenUser = input("Let's build up a dictionary. What user you want to add? (X to quit)")
accounts = {}
while (givenUser != "X"):
givenPassword = input("What's the password for this user?")
accounts[givenUser] = givenPassword
# prepare for next iteration of while loop
givenUser = input("What user do you want to add next? (X to quit)")
print(accounts)
# EXAMPLE 5 - an infinite while loop
# We must be careful that we don't accidentally prohibit the while
# loop from terminating, i.e., that it runs forever. That would make
# it so that our program never stops running.
num = 0
while (num >= 0):
print(num)
num = num + 1