for-loop.py

def is_vowel(ch):
    """String -> Bool

    Determines whether a single char string 
    is a vowel
    """
    return ch == "a" or ch == "e" or ch == "i" or ch == "o" or ch == "u" or ch == "A" or ch == "E" or ch == "I" or ch == "O" or ch == "U"


def remove_vowels(s):
    """String -> String

    Remove all vowels from s
    """
    new_string = ""
    for ch in s:
        if (not is_vowel(ch) and ch != " "):
            new_string = new_string + ch
    return new_string

print(remove_vowels("Hello world!")) # Helloworld!
print(remove_vowels("He llo wor ld!")) # Helloworld!
print(remove_vowels("He    llo wor ld!")) # Helloworld!


# Write the following function that returns 
# a string that is the same as s except that 
# spaces are removed.


def remove_spaces(s):
    """String -> String

    Remove all spaces from s
    """
    new_string = ""
    for ch in s:
        if (ch != " "):
            new_string = new_string + ch
    return new_string

print(remove_spaces("Hello world!")) # Helloworld!
print(remove_spaces("He llo wor ld!")) # Helloworld!
print(remove_spaces("He    llo wor ld!")) # Helloworld!

# Write the following function that returns 
# the number of vowels in string s. Both uppercase 
# and lowercase vowels should be counted. 
# (The vowels are a, e, i, o, and u.)

def is_vowel(ch):
    """String -> Bool

    Determines whether a single char string 
    is a vowel
    """
    return ch == "a" or ch == "e" or ch == "i" or ch == "o" or ch == "u" or ch == "A" or ch == "E" or ch == "I" or ch == "O" or ch == "U"

print(is_vowel("a")) # True
print(is_vowel("b")) # False
print(is_vowel("e")) # True
print(is_vowel("o")) # True
print(is_vowel("A")) # True
print(is_vowel("E")) # True

def num_vowels(s):
    """String -> Num

    Counts the number of vowels in a string
    """
    count = 0
    for ch in s:
        if (is_vowel(ch)):
            count = count + 1
    return count 

print(num_vowels("A")) # 1
print(num_vowels("a")) # 1
print(num_vowels("ab")) # 1
print(num_vowels("aa")) # 2
print(num_vowels("abe")) # 2