pandas indexとreindex

dataframe_make

import pandas as pd
import numpy as np
df=pd.DataFrame(np.arange(9).reshape(3,3))

df
#[Out]#    0  1  2
#[Out]# 0  0  1  2
#[Out]# 1  3  4  5
#[Out]# 2  6  7  8

indexはindex振りなおすけど、値は追随。

reindexはindex振りなおすけど、値は追随しないのでNaN

index

df.index=range(100,103)

df
#[Out]#      0  1  2
#[Out]# 100  0  1  2
#[Out]# 101  3  4  5
#[Out]# 102  6  7  8

reindex

df.reindex(range(100,103))
#[Out]#       0   1   2
#[Out]# 100 NaN NaN NaN
#[Out]# 101 NaN NaN NaN
#[Out]# 102 NaN NaN NaN