reset_index()方法可能最经常使用的地方是处理groupby()方法调用后的数据。官方文档是这样介绍该函数的功能的,As a convenience, there is a new function on DataFrame called reset_index() which transfers the index values into the DataFrames columns and sets a simple integer index. This is the inverse operation of set_index()。即将原来的index设置为列,与set_index()方法的功能相反。
下面,我们来看一些例子:
df=pd.read_excel(r'D:/myExcel/1.xlsx', index_col='id')
>>> dfname score grade
id
a bog 45.0 A
c jiken 67.0 B
i bob 23.0 A
b jiken 34.0 B
g lucy NaN A
e tidy 75.0 B
>>> df.reset_index()id name score grade
0 a bog 45.0 A
1 c jiken 67.0 B
2 i bob 23.0 A
3 b jiken 34.0 B
4 g lucy NaN A
5 e tidy 75.0 B
(2)如果index没有名称,那么默认列名为index。可以通过df.index.name指定了列名之后再调用该方法
>>> df=pd.read_excel(r'D:/myExcel/1.xlsx')
>>> dfid name score grade
0 a bog 45.0 A
1 c jiken 67.0 B
2 i bob 23.0 A
3 b jiken 34.0 B
4 g lucy NaN A
5 e tidy 75.0 B
>>> df.set_index(pd.Series(['f', 'b', 'g', 'm', 'k', 'l']), inplace=True)
>>> dfid name score grade
f a bog 45.0 A
b c jiken 67.0 B
g i bob 23.0 A
m b jiken 34.0 B
k g lucy NaN A
l e tidy 75.0 B
>>> df.index.name='newId'
>>> dfid name score grade
newId
f a bog 45.0 A
b c jiken 67.0 B
g i bob 23.0 A
m b jiken 34.0 B
k g lucy NaN A
l e tidy 75.0 B
>>> df.reset_index()newId id name score grade
0 f a bog 45.0 A
1 b c jiken 67.0 B
2 g i bob 23.0 A
3 m b jiken 34.0 B
4 k g lucy NaN A
5 l e tidy 75.0 B
哈哈,以上就是python小工具关于reset_index的方法的基本介绍。有兴趣欢迎关注公众号:python小工具,一起学习python和pandas