Question

我有这种格式的数据 -

MonthYear  HPI Div State_fips
1-1993  105.45  7   5
2-1993  105.58  7   5
3-1993  106.23  7   5
4-1993  106.63  7   5

Required Pivot Table as: 

Stafips   1-1993    2-1993  3-1993 4-1993
5       105.45  105.58  106.23  106.63

（熊猫新手）

Answer 1

使用unstack或pivot：

df1 = df.set_index(['State_fips', 'MonthYear'])['HPI'].unstack()
MonthYear   1-1993  2-1993  3-1993  4-1993
State_fips                                
5           105.45  105.58  106.23  106.63

df1 = df.pivot(index='State_fips', columns='MonthYear', values='HPI')
MonthYear   1-1993  2-1993  3-1993  4-1993
State_fips                                
5           105.45  105.58  106.23  106.63

但如果重复，需要与groupby或pivot_table合并，mean可以更改为sum，median，...：

print (df)
  MonthYear     HPI  Div  State_fips
0    1-1993  105.45    7           5
1    2-1993  105.58    7           5
2    3-1993  106.23    7           5
3    4-1993  100.00    7           5 <-duplicates same 4-1993, 5
4    4-1993  200.00    7           5 <-duplicates same 4-1993, 5

df1 = df.pivot_table(index='State_fips', columns='MonthYear', values='HPI', aggfunc='mean')
MonthYear   1-1993  2-1993  3-1993  4-1993
State_fips                                
5           105.45  105.58  106.23   150.0 <- (100+200/2) = 150

df1 = df.groupby(['State_fips', 'MonthYear'])['HPI'].mean().unstack()
MonthYear   1-1993  2-1993  3-1993  4-1993
State_fips                                
5           105.45  105.58  106.23   150.0 <- (100+200/2) = 150

最后如果需要从索引创建列并删除列名称：

df1 = df1.reset_index().rename_axis(None, axis=1)
print (df1)
   State_fips  1-1993  2-1993  3-1993  4-1993
0           5  105.45  105.58  106.23   150.0

如何使用Pandas df在Python中水平转动csv中的表？

1 个答案: