我有以下数据和代码来舍入此data.table的选定列:
> dput(mydf)
structure(list(vnum1 = c(0.590165705411504, -1.39939534199836,
0.720226053660755, -0.253198380120377, -0.783366825121657), vnum2 = c(0.706508400384337,
0.526770398486406, 0.863136084517464, 0.838245498016477, 0.556775856064633
), vch1 = structure(c(2L, 4L, 1L, 3L, 3L), .Label = c("A", "B",
"C", "E"), class = "factor")), .Names = c("vnum1", "vnum2", "vch1"
), row.names = c(NA, -5L), class = c("data.table", "data.frame"
))
> mydf[,round(.SD,1),]
Error in Math.data.frame(list(vnum1 = c(0.590165705411504, -1.39939534199836, :
non-numeric variable in data frame: vch1
> cbind(mydf[,3,with=F], mydf[,1:2,with=F][,round(.SD,1),])
vch1 vnum1 vnum2
1: B 0.6 0.7
2: E -1.4 0.5
3: A 0.7 0.9
4: C -0.3 0.8
5: C -0.8 0.6
有没有更好的方法(较短的代码)？谢谢你的帮助。
最佳答案
如果您不介意覆盖原始的mydf:
cols <- names(mydf)[1:2]
mydf[,(cols) := round(.SD,1), .SDcols=cols]
mydf
# vnum1 vnum2 vch1
#1: 0.6 0.7 B
#2: -1.4 0.5 E
#3: 0.7 0.9 A
#4: -0.3 0.8 C
#5: -0.8 0.6 C
关于r - 舍入R中data.table的选定列，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27613310/