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Python Introducing Lists Build an Application Multidimensional Musical Groups

Curtis Thomas III
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Curtis Thomas III
Python Web Development Techdegree Student 655 Points
Posted by Curtis Thomas III
.a{fill-rule:evenodd;}techdegree
Curtis Thomas III
Python Web Development Techdegree Student 655 Points

Join function

I am confused on how to use the join function

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

1 Answer

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

The join method on the string is a very interesting and useful method. The method returns a string representation of a list with the joining string part inserted between each element of the list.

beatles = ["John Lennon", "Paul McCartney", "Ringo Starr", "George Harrison"]
print( ", ".join(beatles))

Note the ", " goes in between each element of the list. Thus... the above code prints the following:

John Lennon, Paul McCartney, Ringo Starr, George Harrison

In the challenge we are given a list or lists. This tipped you off perfectly-- we are going to need a "for" loop to go through the elements of the musical_group variable. But! It is important we join the individual group, and not all the musical_groups as you did.

Your code will look something like 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
s = ", "
for group in musical_groups:
   print( s.join(group) ) # note, print the group, not the entire list of lists.

Your output will like something like this:

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