5. Learn Python | Matrix and Data Frame

This video covers the topic: Some basic operations on Matrices and Data Frames.

1) Matrices and its basic operations like addition, multiplication, determinant, inverse, transpose, matrix to vector, row/column extract, etc.

2) Higher dimensional matrices. In python index start with 0 i.e. 0 th index row/column means 1st row/column.

3) Data Frames: Create, Insert/ delete row/column(s), extract row/column(s) based on some criterion, numerical operations among columns, etc.

I have mainly gone through some useful commands:

1. import numpy : Import Numerical Python library
a) array : Create a matrix
b) [i] : i th row index of 2D Matrix
c) [i,j] : i & j th row index of 2D Matrix
d) [:,i] : i th column index of 2D Matrix
e) [:,[i,j]] : i & j th column index of 2D Matrix
f) [i][j] : (i,j) th element index of 2D Matrix
g) .shape : Dimension
h) .transpose : Transpose
i) .reshape(-1) : Matrix to vector
j) .reshape(a,b) : 2D Matrix
k) .reshape(a,b,c) : 3D Matrix
l) [i] : i th index 3D Matrix
m) [i][j] : j th index row of i th index 3D Matrix
n) [i][[j,k]] : j & k th index row of i th index 3D Matrix
0) [i][:,j] : j th index column of i th index 3D Matrix
p) [i][j][k] : (j,k) th elelment of i th index 3D Matrix
q) @ : Matrix multiplication
r) * : Elelementwise Matrix multiplication
s) .linalg.inv : Inverse
t) .linalg.det : Determinant

2. import pandas : Import Panel Data library
a) DataFrame : Create a dataframe (DF)
b) .head : First few rows of the DF
c) type() : Type of a variable
d) .loc[i] : Selecting i the index row of a DF
e) .insert : Insert a new column
f) .loc[i]= : Insert i th index row
g) .drop : Delete a column
h) .sort_values : Sort w.r.t. a column
i) concat : Merge 2 DFs
j) .describe : Basic summary of columns