My solution for https://github.com/DHS/vowellator

vowellator.py

# My solution for https://github.com/DHS/vowellator

# Assumptions
#
# No names contain spaces
# All names contain vowels
# Names with same first vowel should be returned in same order as inputted

# Additional test cases
#
# ("bond hall squire smith legge", "hall legge smith bond squire"), # every vowel
# ("edwards aldrich toller hall", "aldrich hall edwards toller"),   # multiple a
# ("toller edwards", "edwards toller"),                             # without an a

def vowellate(names_input=None):

    # Can haz vowels
    vowels = ['a', 'e', 'i', 'o', 'u']

    # Set up a dict of lists
    names = {}
    for vowel in vowels:
        names[vowel] = []

    # Loop through list spotting vowels and add to appropriate list
    for name in names_input.split():
        for letter in name:
            if letter in vowels:
                # print('Found a vowel: ' + letter)
                names[letter].append(name)
                break

    # Inspect our glorious creation
    # print(names)

    names_output = ''
    for vowel in vowels:
        if names[vowel]:
            # I don't love this
            names_output += ' ' + ' '.join(names[vowel])

    return names_output[1:]