python pandas 删除行或列

import pandas as pd
import numpy as np

# 构建测试集
df = pd.DataFrame(np.arange(12).reshape(3,4), columns=['a','b','c','d'])
'''
   a  b   c   d
0  0  1   2   3
1  4  5   6   7
2  8  9  10  11
'''

# 删除行
df.drop(2)
df.drop([0,1])

# 删除列
df.drop('a', axis=1)
df.drop(['b','c'], axis=1)
df.drop(columns=['b','c']) # 同上