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Python Functional Python Functional Workhorses Map Comprehension

Posted by Emily Strobl
Emily Strobl
5,429 Points

maps challenge

Create a function named area() that takes a single argument which will be a two-member tuple. area() should return the result of multiplying the first item in the tuple by the second item in the tuple.

i dont understand the task at all

maps.py 
dimensions = [
    (5, 5),
    (10, 10),
    (2.2, 2.3),
    (100, 100),
    (8, 70),
]

2 Answers

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

A tuple is a data type that is similar to a list that contains multiple data items. A tuple differs from a list because it is immutable, that is, once defined it cannot change or be added to.

What the challenge is asking-- create a function "area()" that multiplies the first two items in a tuple and returns the value.

Here is an example that was done with an interactive Python REPL-- The ">>>" indicates where I typed something in to the interactive shell.

Python 3.7.4 (tags/v3.7.4:e09359112e, Jul  8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> # let's name a tuple 'y' and put in three city names
>>> y = ("Chicago", "Denver", "Portland")
>>> # let's access the first or [0] item.
>>> y[0]
'Chicago'
>>> y[1]
'Denver'
>>> # show that we can assign a new variable 'cities' to the value of 'y'
>>> cities = y
>>> cities[0]
'Chicago'
>>> cities[1]
'Denver'
>>> cities[2]
'Portland'
>>> # show that if we try to access an item that is not in the list, we get an error
>>> cities[3]
Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    cities[3]
IndexError: tuple index out of range
>>> # suppose we have a simple dimension tuple variable named "x"
>>> # note, a tuple is typically defined using parenthesis.
>>> x = (5,5)
>>> # we can easily create a function that can multiply the first and second items of the dimension
>>> def area(dim):
        return dim[0] * dim[1]

>>> # now, let's calculate an "area" of the dim variable
>>> area(x)
25
>>>

I hope this helps your understanding! Good luck with your Python journey!

Emily Strobl
Emily Strobl
5,429 Points

this helped a lot thank you

Ryan McGuire
Ryan McGuire
3,758 Points
Ryan McGuire
Ryan McGuire
3,758 Points

Such a great explanation!

Zimri Leijen
Zimri Leijen
11,835 Points
Zimri Leijen
Zimri Leijen
11,835 Points

a tuple in python is a collection of data, for example:

("apple", "banana", "cherry") is a tuple with 3 items.

You are asked to make a function that takes a tuple (with two values as input) and will give the result of multiplying the two values in that tuple as a result.

That function should be named area()