[英]Sort by one column, then group by another, in Pandas Dataframe?
这是一种与我可以用类似措辞找到的问题相反的问题,例如:
说,我有这个 DataFrame:
import pandas as pd
df = pd.DataFrame({
'model': ['Punto', 'Doblo', 'Panda', 'Doblo','Punto', 'Tipo'] ,
'timestamp': ['20200124_083155', '20200124_122052', '20200124_134350', '20200124_150801', '20200124_163540', '20200124_195955']
})
print(df)
这打印出来:
model timestamp
0 Punto 20200124_083155
1 Doblo 20200124_122052
2 Panda 20200124_134350
3 Doblo 20200124_150801
4 Punto 20200124_163540
5 Tipo 20200124_195955
我想获得的是:首先按时间戳排序; 然后按照出现的顺序,按出现的顺序分组 - 但没有熊猫.groupby
子句将添加的额外“分组”列; 也就是说,我想获得最终输出:
model timestamp
0 Punto 20200124_083155
1 Punto 20200124_163540
2 Doblo 20200124_122052
3 Doblo 20200124_150801
4 Panda 20200124_134350
5 Tipo 20200124_195955
我怎样才能做到这一点?
我认为这可以通过有序分类,在第一步中按排序的timestamp
值设置顺序,然后按DataFrame.sort_values
对两列进行DataFrame.sort_values
:
c = df.sort_values('timestamp')['model'].unique()
df['model'] = pd.Categorical(df['model'], ordered=True, categories=c)
df = df.sort_values(['model','timestamp'])
print (df)
model timestamp
0 Punto 20200124_083155
4 Punto 20200124_163540
1 Doblo 20200124_122052
3 Doblo 20200124_150801
2 Panda 20200124_134350
5 Tipo 20200124_195955
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.