我有一个像这样的数据框:
item price source day
book 5 shop 2012-01-01
car 100 shop 2012-01-01
desk 10 shop 2012-01-01
book 4 internet 2012-01-01
car 99 internet 2012-01-01
desk 9 internet 2012-01-01
book 6 shop 2012-01-02
car 101 shop 2012-01-02
desk 11 shop 2012-01-02
book 4 internet 2012-01-02
car 100 internet 2012-01-02
desk 10 internet 2012-01-02
我希望每天每件商品的每个价格,例如:
item price.shop price.internet day
book 5 4 2012-01-01
car 100 99 2012-01-01
desk 10 9 2012-01-01
book 6 5 2012-01-02
car 101 100 2012-01-02
desk 11 10 2012-01-02
我一直在努力
melt
'ing 然后
cast(df, item ~ source + variable)
却得不到想要的结果。我认为问题在于我本质上有两个“每件事”条件(每day
,每source
),所以没有正确的等式。
谢谢你的帮助