Understanding Axis In Pandas

Basic Concepts

• axis = 0: Refers to rows, Operations are performed on each column.
• axis = 1: Refers to columns, Operations are performed on each row.

Examples

import pandas as pd
df = pd.DataFrame({
    'A': [1, 2, 3], 
    'B': [4, 5, 6], 
    'C': [7, 8, 9]
    })

sum_0 = df.sum(axis=0) # axis = 0, means rows,  Column-wise sum
print(sum_0)
"""
A     6
B    15
C    24
dtype: int64
"""

sum_1 = df.sum(axis=1) # axis = 1, means columns, Row-wise sum
print(sum_1)
"""
0    12
1    15
2    18
dtype: int64
"""

Column-wise
Row-wise
“-wise” 是一个常见的英语后缀，加在名词后构成副词，表示“就……而言”或“按照……的方式”