[HackerRank] All Domains - Python - Basic Data Types - Finding the percentage

A dictionary is a data type which stores values in pairs. For each element in the dictionary, there is a unique key that points to a value. A dictionary is mutable. It can be changed. 
For example:

a_dict = {'one': 1} # Here 'one' is the key.   

Note: The key of a dictionary is immutable. We cannot use a list as a key because a list is mutable. But we can make a tuple of list and use as key.

a_dict['two'] = 2 # Adds key 'two' which points to 2 print a_dict['one'] # prints 1   if 'three' in a_dict:     # To check whether a certain string exist as a key in the dictionary       print a_dict['three'] else:       print "Three not there" # prints Three not there del a_dict['one'] # Deletes index 'one' and the value associated with it   print a_dict # prints {'two': 2} 

Note: A dictionary is unordered. So, only use the keys to navigate through the dictionary.

 

 

---------------------------------------------------------------------

N = int(input())dictionary = {}for i in range(0, N):    inputArray = input().split()    marks = list(map(float, inputArray[1:]))    dictionary[inputArray[0]] = sum(marks)/float(len(marks))

print("%.2f" % dictionary[input()])

---------------------------------------------------------------------