Question

我有以下代码行，它从数据框“Diff”中提取某些列。应用data.table函数时，列名称将重命名为V1，V2，V3等。如何保持列名与以前相同（因为它们出现在Diff数据帧中）？

data.table(Diff$FactSet.Fund.Code, Diff$FactsetDate.x, , Diff$DeskName.x)

Answer 1

假设当您从data.frame转到data.table时出现问题，您可以先使用diff <- data.table(diff)将data.frame完整地转换为data.table。然后您可以使用subset()以及包含要保留的列名称的列表轻松对data.table进行子集化。这样您就可以保留原始名称。这是：

# Libraries
library(data.frame)

# Here's dataframe with some random data
# that fits your description:
diff = data.frame(FactSet.Fund.Code=rep(c("a","b"),c(2,3)),FactsetDate.x=1:5,FactsetSomethingelse=5:1)
#class(diff)

diff = data.table(diff)
#class(diff)

# The names fo the columns you'd like to keep:
selection = c('FactSet.Fund.Code','FactsetDate.x')

# Your desired subset:
diff <- subset(diff,,selection)

# And now it should look like this:

   FactSet.Fund.Code FactsetDate.x
1:                 a             1
2:                 a             2
3:                 b             3
4:                 b             4
5:                 b             5

应用Data.table函数后，保持列名相同

1 个答案: