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!

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

Edward Randall
Edward Randall
1,834 Points

How do I do this problem?

How do I do this problem?

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 musical_groups

1 Answer

Chris Freeman
Chris Freeman
Treehouse Moderator 68,404 Points

Hey Edward Randall, let’s break down the task:

The given outer list contains group members contained in a list, aka a list-of-lists.

  • Can you loop through each group [in the outer list]...

This is the usual loop through a list:

for inner_list in outer_list:
  • output the members joined together with a ", " comma space as a separator

A list can be joined together into a string using the str.join() method. This uses a string as the glue characters between a list of strings. So,

β€œ, β€œ.join(inner_list)

Creates a larger string with inner_list items comma-space separated.

Post back if you need more help. Good luck!!!