Numpy in Python | (Data Science ss : 7)

Numpy in Python

NOTE : *python does not have array it is build on list only*

*What is Numpy ?

• Numpy is used for mathematical & Logical operations on the arrays.
• It provides features for multi dimensional array & matrices in python too.
• Numpy has more features than list.
• The unique thing about Numpy is that you can put list or tuple it will convert it to numpy array.
• Numpy does not come by default with python if you wanna use it : go to command prompt and type : pip install numpy 
• It does not come with python by default that's why we are using jupyter because it come's in it.
• Now go to Anaconda > jupyternotebook > Click on ( New ) > Select Python3
• Click shift+enter to run the code.

As you all know what what python can do; now it's time to explore it. So go to your jupyter notebook & lets get started. If you don't know what jupyter notebook is then check out my Installing Anaconda blog. 

1.) Creating Numpy array : 

Python numpy support both 1 dimensional as well as 2 dimensional array : 

(i) 1D array :

import numpy as np

a=np.array([1,2,3])

b=np.array((4,5,6))

print(a)

print(b)

>>[1,2,3]

     [4,5,6]

(ii) 2D array :

import numpy as np

a=np.array([[1,2,3],[4,5,6]])

print(a)

>>[[1,2,3]

      [4,5,6]]

As you all see that our output is already converted into the array/List what ever suits you call that.
As you can see it is converted into List & if you read my sequence blog you must be familiar with List & probably know that list's are mutable/editable.
Now this factor of list will be very useful for us; now we can use List in many ways.

(iii) N-D array :

• Most important object defined in Numpy is an N-Dimension array type called ndarray.
• In real world we don't use that much array we use max to max 3 dimension's. 
• Describe collection of items of the same type.
• Items can be accessed using a zero based index.
• Every item in an ndarray takes the same size of block in the memory.
• Each element in ndarray is an object of data-type object (called dtype).