Hello peeps! After a detailed study I bring to you a summarized python blog that you will need to know before you get started.

This is the module one , will have more coming up later….I have tried my best to cover variables, lists, functions, methods and packages with some useful examples. It is a short read with useful content hence , do give it a read to brush up with a quick revision if you are already familiar.

Variables

Variables have associated values assigned to a name or reference.

Data Types of variables :

• int for integers
• float for real numbers
• Boolean for true and false
• string for text

2 important functions related to variables :

• To convert one data type to other:   float(variable name)

Ex. Print(“hey”+ str(5) + “years from now”)

• To get type of variable

Type(variable) or print(type(var))

EXAMPLE: A,B and C are variables of different type

• A=5
• B=”hey”
• C=5.56

LISTS

• It is a compound data type.
• Collection of objects under a single name.
• Can have different data type objects including sublists.
• List type has specific functionality and behaviour.

Sub-setting or accessing a list:

Indexing basically starts from 0

To access ,

•  The third element in the list    list[2]
• The last element in the list       list [-1]

Slicing a list : getting a range of values from the list

Syntax:

Example:

• List[3:]    4^th element to the last
• List[:4]    from beginning till the fourth element
• List[-4:]    last four elements

Manipulating lists: Add, change or remove elements from a list.

• Adding :  done by “+” symbol

Ex: List + [“hey”]   –adds element to existing list

• Deleting element:  done by del function ,it immediately updates the indexing values as per the new list.

Del(list[3]) -deletes 4^th element of the list

• Changing or updating list with assignment operator i.e =

List[3]=5    , will change the 4^th element to 5

NOTE:

The variables are actually reference to the same data element .              For example,
X is a list,
Y is another list with values of X
If Y is updated, then values in X will change too.

To avoid such scenarios,

Copy list as :

Y = list(X)    or using slice method:   Y =X[:]

Fun Fact : “;” in python is used to  place commands in same line,

Functions

Function is a Piece of reusable code, it is used to solve a particular task

Some example of standard built-in functions:

• Type(var)
• Max()- gives maximum element in a list ,passed as parameter
• Round()- can have one or two parameters:

Syntax:

Round (number, precision)

Round (number)— round it off  to nearest integer

• Len(var) -gives length

• Help(function name) will tell you the functionalities of the function, or how to use a particular in built function.

Fun Fact : square brackets in help function indicate that the parameter may or may not be added.

Sorting in python:

Remember those days when we had to do the tedious job of writing 5-6 lines of code for sorting, well python provides that as an in-built function, via sorted

 sorted() takes three arguments: iterable, key and reverse

By default key is none and reverse is false.

Ex: sorted(list,key=None,reverse=True)   will return a descending ordered list

METHODS:

Methods are functions that belong to an object , every object depending on its type has associated methods

List methods : count() , index()

• List.count(4)  – returns number of times 4 occurs in the list
• List.index()    -returns the index of the list

Some other list methods:

• append(), that adds an element to the list it is called on,
• remove(), that removes the first element of a list that matches the input, and
• reverse(), that reverses the order of the elements in the list it is called on

String methods:

string.capitalise()-  puts your string’s first letter in caps

string.replace(‘s’,’ze’) -will replace s in your string with ze

string.upper()- will capitalise the entire string

Packages

Having all the functions in a large code database can be difficult to maintain and can be very messy to extract.

Hence python introduces a unique feature i.e packages

Packages is directory of python scripts (or modules). It has specific function,modules and type

Packages that we have seen earlier are :

• Numpy for arrays
• Matplotlib for data visualisation
• scikit learn for machine learning Installing and importing packages

Here’s a very easy way to installing and importing your packages:

Importing your package:

• IMPORTING WITH ALIAS:
  • import numpy as np
  • np.array([1,2,3])
• SELECTIVE IMPORTING:
  • import numpy as array
  • array([1,2,3])

That’s all for today folks, most of y’all might know the basics that i have covered in this blog , but I believe that that basics build up the ideals of the subject. Hence, I started with the very first fundamentals of ML with python. Enjoy and have a great day! Please like if you found this useful in any way:)