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Python Introducing Lists Build an Application Multidimensional Musical Groups

Posted by Eric Nachtsheim
Eric Nachtsheim
2,006 Points

I am stuck on Challenge 1 of 2 on Multidimensional Music Groups. I'm not sure how to use join/separate here.

Honestly, just not sure how join and separate work with multidimensional lists. Might not understand them well enough in general, and I'm really unsure how to proceed.

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"],
]
# Your code here
for groups in musical_groups:
    for member in groups:
        print(member.join(", "))

3 Answers

Peter Vann
Peter Vann
36,427 Points
Peter Vann
Peter Vann
36,427 Points

Hi Eric!

It looks like you were trying to use more of a JavaScript type of syntax and you had one loop too many.

This passes the first task:

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"],
]
# Your code here
for members in musical_groups:
    print( ", ".join(members) )

More info:

https://www.w3schools.com/python/ref_string_join.asp

This passes the second task:

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"],
]
# Your code here
for members in musical_groups:
    if len(members) == 3:
        print( ", ".join(members) )

More info:

https://www.tutorialspoint.com/python/list_len.htm

https://www.tutorialspoint.com/python/tuple_len.htm

I hope that helps.

Stay safe and happy coding!

Eric Nachtsheim
Eric Nachtsheim
2,006 Points
Eric Nachtsheim
Eric Nachtsheim
2,006 Points

I see. Let me make sure I have this right. print( ", ".join(members) ) What this does is join every item in the inner lists (is that the right terminology? Not sure) together as a string. Then each string is looped through, printing each one in its own line. Is that in the ballpark?

In any case, thank you so much for your help. I really appreciate it.

Peter Vann
Peter Vann
36,427 Points
Peter Vann
Peter Vann
36,427 Points

Yes - you are in the ballpark.

This is the output for the second task:

Ad Rock, MCA, Mike D.
Salt, Peppa, Spinderella
Run, DMC, Jam Master Jay

Again, I hope that helps.

Stay safe and happy coding!