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Python Introducing Lists Build an Application Multidimensional Musical Groups

John . Meredith
John . Meredith
2,020 Points
Posted by John . Meredith
John . Meredith
2,020 Points

Can not figure out this question?

here is my answer

for groups in musical_groups: groups = ",".join(groups) print(groups)

groups.py 
musical_groups = [
    ["Ad Rock", "MCA", "Mike D."],
    ["John Lennon", "Paul McCartney", "Ringo Starr", "George Harrison"],
    ["Salt", "Peppa", "Spinderella"],
    ["Rivers Cuomo", "Patrick Wilson", "Brian Bell", "Scott Shriner"],
    ["Chuck D.", "Flavor Flav", "Professor Griff", "Khari Winn", "DJ Lord"],
    ["Axl Rose", "Slash", "Duff McKagan", "Steven Adler"],
    ["Run", "DMC", "Jam Master Jay"],
]
for groups in musical_groups: 
    groups = ", ".join(groups)
    print(groups)

2 Answers

Joseph Yhu
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,638 Points
Joseph Yhu
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,638 Points

Remove the last line, and replace groups = ", ".join(groups) with print(", ".join(groups)).

Edit: Never mind; your way works too. Do you perhaps have trouble with the 2nd part? Because you should pass the 1st part with your solution.

Jeff Muday
MOD
Jeff Muday
Treehouse Moderator 28,722 Points
Jeff Muday
Jeff Muday
Treehouse Moderator 28,722 Points

You are very close to the answer, nice work so far!

What Joseph is saying is this-- the join() method of the string is a sort-of virtual loop that concatenates all musical groups into a single group string with punctuation.

musical_groups = [
    ["Ad Rock", "MCA", "Mike D."],
    ["John Lennon", "Paul McCartney", "Ringo Starr", "George Harrison"],
    ["Salt", "Peppa", "Spinderella"],
    ["Rivers Cuomo", "Patrick Wilson", "Brian Bell", "Scott Shriner"],
    ["Chuck D.", "Flavor Flav", "Professor Griff", "Khari Winn", "DJ Lord"],
    ["Axl Rose", "Slash", "Duff McKagan", "Steven Adler"],
    ["Run", "DMC", "Jam Master Jay"],
]

groups = ", ".join(groups)
print(groups)

It is equivalent to this messier construct shown below. There is a nice way to do it with "List Comprehensions" but that is beyond the scope of what you asked.

musical_groups = [
    ["Ad Rock", "MCA", "Mike D."],
    ["John Lennon", "Paul McCartney", "Ringo Starr", "George Harrison"],
    ["Salt", "Peppa", "Spinderella"],
    ["Rivers Cuomo", "Patrick Wilson", "Brian Bell", "Scott Shriner"],
    ["Chuck D.", "Flavor Flav", "Professor Griff", "Khari Winn", "DJ Lord"],
    ["Axl Rose", "Slash", "Duff McKagan", "Steven Adler"],
    ["Run", "DMC", "Jam Master Jay"],
]

groups = None # groups is the string to be printed, start with None
for group in musical_groups: 
    if groups is None:
        # first time through the loop
        groups = group
    else:
        groups += ', ' + group
print(groups)