How to use the drop() function in Python Pandas?

Python basic pandas drop() usage

I used pandas when doing data processing, and the experience is good. The record is as follows:

import pandas as pd
import numpy as np

You can directly use pandas to generate a random array

df = pd.DataFrame(np.random.randn(5,3),index = list('abcde'),columns = ['one','two','three'])

Assume there are empty numbers:

df.ix[1,:-1] = np.nan  #第二行，排除倒数第一个都是Nan
df.ix[1:-1,2] = np.nan #第三列，排除第一个和最后一个都是Nan

Delete all the Nan ones

print('\n',df.dropna())

Selectively delete, rather than delete Nan

print(df.drop(['one'],axis=1))
print(df.drop(['a','c'],axis = 0))

Additional: python pandas drop() function

Use of drop function

(1) drop() delete rows and columns

drop([ ],axis=0,inplace=True)

• ##drop([ ]), delete a certain row by default;

• If you want to delete a column, axis=1 is required;

• The parameter inplace is deleted by default False means keeping the original data unchanged, and True means changing the original data.

import pandas as pd
 
import numpy as np
 
data=pd.DataFrame(np.arange(20).reshape((5,4)),columns=list('ABCD'),index=['a','b','c','d','e'])
print(data)
print('*'*40)
print(data.drop(['a'])) #删除a 行，默认inplace=False,
print('*'*40)
print(data)#  data 没有变化
print('*'*40)
print(data.drop(['A'],axis=1))#删除列
print('*'*40)
print(data.drop(['A'],axis=1,inplace=True)) #在本来的data 上删除
print('*'*40)
print(data)data 发生变化

 
    A   B   C   D
a   0   1   2   3
b   4   5   6   7
c   8   9  10  11
d  12  13  14  15
e  16  17  18  19
****************************************
    A   B   C   D
b   4   5   6   7
c   8   9  10  11
d  12  13  14  15
e  16  17  18  19
****************************************
    A   B   C   D
a   0   1   2   3
b   4   5   6   7
c   8   9  10  11
d  12  13  14  15
e  16  17  18  19
****************************************
    B   C   D
a   1   2   3
b   5   6   7
c   9  10  11
d  13  14  15
e  17  18  19
****************************************
None
****************************************
    B   C   D
a   1   2   3
b   5   6   7
c   9  10  11
d  13  14  15
e  17  18  19

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