Python - Week 2 - Comprehensions

Python provides multiple idioms to get things done. Comprehensions is one such construct.

Lets look at how it is used in simple ways.

With a given integral number n, write a program to generate a dictionary that contains (i, i*i) such that is an integral number between 1 and n (both included). 
And then the program should print the dictionary. 

Suppose the following input is supplied to the program: 8 

Then, the output should be: {1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64}



What did we learn here:

  1. print was a statement in 2.x. In 3.x it is a function.
  2. Dictionaries store objects by key.
  3. Because dictionaries are unordered collections, operations that depend on a fixed positional order (e.g., concatenation, slicing) don’t make sense. Instead, dictionaries are the only built-in, core type representatives of the mapping category — objects that map keys to values.
Location: New Delhi, Delhi, India

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