functional_programming.py

states = ["Kansas", "Nebraska", "North Dakota", "South Dakota"]

def urlify(string):
    """Converts a string into a URL-friendly string."""
    return string.lower().replace(" ", "-")

#urls: imperative version
def imperatitve_urls(states):
    urls = []
    for state in states:
        urls.append(urlify(state))
    return urls

print(imperatitve_urls(states))

#urls: functional version, list comprehension
def functional_urls(states):
    return [urlify(state) for state in states]

print(functional_urls(states))

#singles: imperative version
def imperatitve_singles(states):
    singles = []
    for state in states:
        if len(state.split()) == 1:
            singles.append(state)
    return singles

print(imperatitve_singles(states))

#list comprehension to print only even numbers
print([n for n in range(10) if n % 2 == 0])

#singles: funcationl version
def functional_singles(states):
    return [state for state in states if len(state.split()) == 1]

print(functional_singles(states))

#lengths: imperative version
def imperative_lengths(states):
    lengths = {}
    for state in states:
        lengths[state] = len(state)
    return lengths

print(imperative_lengths(states))

#lengths: functional version
def functional_lengths(states):
    return{state: len(state) for state in states}

print(functional_lengths(states))

#genertor comprehension
squares = (n**2 for n in range(10**8 + 1)) 

#set comprehension with intersection
print({n for n in range(5,21)} & {n for n in range(10) if n % 2 ==0})

#set comprehension with union
print({n for n in range(5,21)} | {n for n in range(10) if n % 2 ==0})

numbers = range(0, 101)

#sum: imperative solution
def imperative_sum(numbers):
    total = 0
    for n in numbers:
        total += n
    return total

print(imperative_sum(numbers))

#sum: functional (and built in) solution
print(sum(numbers))