通过组合两列的信息在R中构造数据帧

Question

我有一个由两列组成的数据框：true.de.status和decision.de。数据集可重现如下：

dat = structure(c(0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 
0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 
0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 
0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0), .Dim = c(100L, 
2L), .Dimnames = list(NULL, c("true.de.status", "decision.de"
)))

dat的前几行是：

       true.de.status decision.de
  [1,]              0           0
  [2,]              0           0
  [3,]              1           1
  [4,]              0           1
  [5,]              1           0
  [6,]              0           0
  [7,]              1           1
  [8,]              1           0

现在我希望用x轴绘制基因数量（即dat中的总行数）和y轴真实阳性数的图。 x轴很容易确定：seq(0,100)会给我0,1，......，100个基因。对于y轴，我需要根据两列true.de.status和decision.de计算：当我遍历每一行时，我可以计算真实的阳性随着基因（行）的数量增加。例如，

first 1 gene included: True positive (TP) = 0
first 2 genes included: TP = 0
first 3 genes included: TP = 1 (since both columns have 1 and they match)
first 4 genes included: TP = 1 (`decision.de` is 1, but `true.de.status` is 0, so it is a false positive)
first 5 genes included: TP = 1 (two columns don't match)
......

是否有一种简单的方法可以操纵dat数据框，并返回与dim(dat)[1]长度相同且长度为正数的向量？谢谢！

Answer 1

看起来你想要

df <- as.data.frame(dat)
df$TP <- cumsum(as.numeric(df$true.de.status == 1 & df$decision.de == 1))

这将返回两列均为1且匹配的实例的累计计数。

Answer 2

看看这是否是你想要的：

plot( cumsum( dat[ , "true.de.status"] == 1 &
              dat[ , "decision.de"] == 1) , 
      type="s")

（默认情况下，x值为1:100。如果你想要点或线，你可以改变类型参数。显然你可以使用vec <- ...将cumsum值分配给一个名字）