Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Introducing Lists Build an Application Multidimensional Musical Groups

Joshua Thao
Joshua Thao
6,439 Points

Do I need 2 for loops here? How am I suppose to find out how many names are in each list?

I know I am suppose to use a if loop here something like if [i] == 3: print(", ".join(names)) ??? Any hints?

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 name in musical_groups:
    if musical_groups is 3:
        print(", ".join(name))

1 Answer

Steven Parker
Steven Parker
231,269 Points

You don't need another loop, but here's a few hints:

  • you don't want the identity operator here ("is"), use equality instead ("==")
  • the "len" function will give you the size of a list
  • be sure to test the "name" list instead of the whole "musical_groups" list