[英]R using dcast,melt and concatenation to reshape data frame
我有一个数据框,如下所示:
mydf <- data.frame(Term = c('dog','cat','lion','tiger','pigeon','vulture'), Category = c('pet','pet','wild','wild','pet','wild'),
Count = c(12,14,19,7,11,10), Rate = c(0.4,0.7,0.3,0.6,0.1,0.8), Brand = c('GS','GS','MN','MN','PG','MN') )
结果数据帧:
Term Category Count Rate Brand
1 dog pet 12 0.4 GS
2 cat pet 14 0.7 GS
3 lion wild 19 0.3 MN
4 tiger wild 7 0.6 MN
5 pigeon pet 11 0.1 PG
6 vulture wild 10 0.8 MN
我希望将此数据帧转换为以下结果resultDF
Category pet wild
Term dog,cat,pigeon lion,tiger,vulture
Countlessthan13 dog,pigeon tiger,vulture
Ratemorethan0.5 cat tiger,vulture
Brand GS,PG MN
行标题指示类似Countlessthan13之类的操作,这意味着将Count <13应用于术语,然后进行分组。 另请注意,品牌名称是唯一的而不是真实的。
我已经尝试过dcast并融化了...但是没有得到想要的结果。
我们可以使用data.table
做到这data.table
。 将'data.frame'转换为'data.table'( setDT(mydf)
),按'Category'分组,通过paste
'Term'的unique
值setDT(mydf)
小于13或'比率”大于0.5,并paste
“品牌”的unique
元素。
library(data.table)
dt <- setDT(mydf)[, .(Term = paste(unique(Term), collapse=","),
Countlesstthan13 = paste(unique(Term[Count < 13]), collapse=","),
Ratemorethan0.5 = paste(unique(Term[Rate > 0.5]), collapse=","),
Brand = paste(unique(Brand), collapse=",")), by = Category]
从汇总数据集('dt')中,我们通过将'id.var'指定为'Category' melt
为'long'格式,然后dcast
其dcast
为'wide'格式。
dcast(melt(dt, id.var = "Category", variable.name = "category"),
category ~Category, value.var = "value")
# category pet wild
#1: Term dog,cat,pigeon lion,tiger,vulture
#2: Countlesstthan13 dog,pigeon tiger,vulture
#3: Ratemorethan0.5 cat tiger,vulture
#4: Brand GS,PG MN
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