Functions: intermediate 7/12

Q&A
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#1

https://app.dataquest.io/m/316/functions%3A-intermediate/7/more-about-tuples

This was the assignment.

  1. Use the open_dataset() function to open the AppleStore.csv file, which has a header row.
  2. Do the variable assignment step in a single line of code.
  • Assign the header to a variable named header.
  • Assign the rest of the dataset to a variable named apps_data.
def open_dataset(file_name='AppleStore.csv', header=True):        
    opened_file = open(file_name)
    from csv import reader
    read_file = reader(opened_file)
    data = list(read_file)
    
    if header:
        return data[1:], data[0]
    else:
        return data

apps_data, header = open_dataset()

This is the solution code provided by DQ. I don’t understand how this works, when is apps_data being defined?

#2

Can you please clarify what you mean by this?

Because you did share the code where it’s defined -

#3

I guess, how does Python know apps_data refers to the whole dataset minus the header?

#4

Your function is supposed to return two values.

One value is the header. The other is the dataset without the header.

return data[1:], data[0]

Then, when you call the function

apps_data, header = open_dataset()

You save the output of the function (those two values in the return statement) into the two variables, apps_data and header respectively.

#5

Ah, I see, that’s super clear now! Thanks so much!

1 Like
#6

why is the answer wrong when you invert the code:

header, apps_data = open_dataset()

#7

Because when you change the variable names they will store different values than what the grader expects them to.