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Python Introducing Lists Build an Application Multidimensional Musical Groups

Posted by Thomas Wilhelm
Thomas Wilhelm
3,714 Points

Need help on Step 1 of Multidimensional Musical Groups!

I'm getting the error of it expecting a str object but hitting a list object. I'm not sure how to get it converted to a string. Would someone be able to walk me through the process? I think I found the answer, but I don't recall going over it, nor do I understand it. The goal of it is to print every list within this musical_groups list separated by ", ".

Thank you!

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 group in musical_groups:
    band = ", ".join(musical_groups)
    print(band)
Filipe Martins
Filipe Martins
2,824 Points
Filipe Martins
Filipe Martins
2,824 Points

What are you expecting as output ? all names separated by "," ?

Thomas Wilhelm
Thomas Wilhelm
3,714 Points

Right, sorry. So you are supposed to print out each individual list, separated by ", "

2 Answers

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

You're close, but it's not the entire "musical_groups" array that you want to join and print, but each individual "group". :wink:

    band = ", ".join(group)
Thomas Wilhelm
Thomas Wilhelm
3,714 Points
Thomas Wilhelm
Thomas Wilhelm
3,714 Points

OK. So after pondering it over the course of the day (or really just stepping away for work then trying it again, I settled on this:

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
a = 0
for group in musical_groups:
    band = ", ".join(musical_groups[a])
    print(band)
    a += 1

Which worked! So...moving on. Thank you!

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

That works, but the loop has already isolated the specific "group" for you so you can do it a bit more simply and without the need for the separate indexing variable ("a").

See the example I added to my answer.