Python collections, Part -I

prakx1 — Thu, 24 Dec 2020 06:09:12 +0000

Python always surprises and this time it made my work a lot easier so I am writing this

Python collections are container datatypes.So, what are they?Container datatypes are data structures that store other objects(integers,string,list user-defined objects) and also provide a way to access and traverse them.

Python provides some of these container datatypes in collections module to make it easier to store and access items.In this first part we will see counter.
It returns a dictionary with the keys as the elements of the object with the count of the element as the value.
Let's see an example:

>>> from collections import Counter
>>> c = Counter("ABCDABC")
>>> c #returns the count of each letter in string
Counter({'A': 2, 'B': 2, 'C': 2, 'D': 1})

>>> from collections import Counter
>>> c = Counter(['python','collections','are','interesting'])
>>> c #returns the counts of each element in list
Counter({'python': 1, 'collections': 1, 'are': 1, 'interesting': 1})
>>>

Getting values from counter:

>>> c['collections']
1 #collecctions appeared only once
>>> c['interesting']
1 #intersting appeared only  once  
>>> c['movie']
0 # 'movie' is not present so the output is 0
>>>

Note: Trying to get values not present in counter return 0.
For more
References:
Python documentation
Container
Thanks and merry Christmas

What is Duck typing in Python

prakx1 — Thu, 19 Nov 2020 12:42:11 +0000

Duck typing got it's name from Duck test-"If it walks like a duck and it quacks like a duck, then it must be a duck".

In python (and other dynamically typed languages)it doesn't matter what is the type of object what matters is that what it do.

class Elephant:
    def fly(self):
        print("Elephant is flying")


class Duck:
    def fly(self):
        print("Duck is flying")

Take the two objects elephant and duck with same method fly.Let us create a function animal_flying that makes the animal fly.

def animal_flying(animal):
    animal.fly()
animal_flying(Duck())
animal_flying(Elephant())

[Output]:

Elephant is flying
Duck is flying

The function makes both duck and elephant fly without checking there type as both have the fly method, and this feature of using a object depending upon the methods it has irrespective of its type is called Duck typing.

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Python collections, Part -I

What is Duck typing in Python