pythonpandas中reset_index方法的使用

reset_index&＃xff08;&＃xff09;方法可能最经常使用的地方是处理groupby&＃xff08;&＃xff09;方法调用后的数据。官方文档是这样介绍该函数的功能的&＃xff0c;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&＃xff0c;与set_index&＃xff08;&＃xff09;方法的功能相反。
下面&＃xff0c;我们来看一些例子&＃xff1a;

df&＃61;pd.read_excel(r&＃39;D:/myExcel/1.xlsx&＃39;, index_col&＃61;&＃39;id&＃39;)
>>> 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


# 将index恢复为id列
>>> 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


&＃xff08;2&＃xff09;如果index没有名称&＃xff0c;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&＃61;pd.read_excel(r&＃39;D:/myExcel/1.xlsx&＃39;)
>>> 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([&＃39;f&＃39;, &＃39;b&＃39;, &＃39;g&＃39;, &＃39;m&＃39;, &＃39;k&＃39;, &＃39;l&＃39;]), inplace&＃61;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
# 为index指定个名字
>>> df.index.name&＃61;&＃39;newId&＃39;
>>> 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&＃xff0c;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&＃xff1a;python小工具&＃xff0c;一起学习python和pandas