r - 更改 dcast 以显示多列

Question

我有以下情况。考虑以下 df:

mymatrix <- as.data.frame(matrix(data = 0, nrow = 7, ncol = 4))
colnames(mymatrix) <- c("Patient", "marker", "Number", "Visit")

mymatrix[,1] <- c("B1","B1","C1","C1","D1","D1","D1")
mymatrix[,2] <- c("A","A","A","A","A","A","A")
mymatrix[,3] <- c(1,0,0,15,1,2,13)
mymatrix[,4] <- c("baseline","followup","baseline","followup","baseline","followup","followup")

> mymatrix
  Patient marker Number    Visit
1      B1      A      1 baseline
2      B1      A      0 followup
3      C1      A      0 baseline
4      C1      A     15 followup
5      D1      A      1 baseline
6      D1      A      2 followup
7      D1      A     13 followup

如果我在前 6 行做 dcast，我会得到:

> dcast(mymatrix[1:6,], Patient +marker~Visit, value.var = "Number")
  Patient marker baseline followup
1      B1      A        1        0
2      C1      A        0       15
3      D1      A        1        2

如果我对我得到的所有行进行 dcast:

> dcast(mymatrix, Patient +marker~Visit, value.var = "Number")
Aggregation function missing: defaulting to length
  Patient marker baseline followup
1      B1      A        1        1
2      C1      A        1        1
3      D1      A        1        2

有没有办法而不是默认长度它会添加第二个后续列？所以数据会显示如下:

  Patient marker baseline followup.1 followup.2
1      B1      A        1        0     NA
2      C1      A        0        15     NA
3      D1      A        1        2     13

谢谢!

Answer 1

不清楚您在问什么，因为您似乎想在 dcast 中组合两个不同的功能同时。在我看来，您想改进第一个输出而不是第二个输出。如果是这样，一个简单的解决方案就是为 Visit 中的值添加一个自动索引。列然后 dcast .这是使用 data.table 的简单方法包(认为输出不是你想要的，因为我还添加了一个索引 baseline ，但它可以让你开始)

library(data.table)
setDT(mymatrix)[, Visit := paste(Visit, seq_len(.N), sep = "."), list(Patient, Visit)]
dcast.data.table(mymatrix, Patient + marker ~ Visit, value.var = "Number")

#    Patient marker baseline.1 followup.1 followup.2
# 1:      B1      A          1          0         NA
# 2:      C1      A          0         15         NA
# 3:      D1      A          1          2         13