R检索矩阵中条件下的列名

我有一个值为0或1的矩阵。当一行只有一个“1”时，我想返回列名，其中是“1”值，在任何其他情况下，得到“0”。对于以下示例：

test <- matrix(c(0,1,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,1,0,0),ncol=5)
colnames(test) <- c('c1','c2','c3','c4','c5')

好了：

test <- matrix(c(0,1,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,1,0,0),ncol=5)
colnames(test) <- c('c1','c2','c3','c4','c5')

result <- data.frame(test, result = apply(test, 1, function(row){ if(sum(row)==1)colnames(test)[[which(row==1)]]else 0}))

---

test我会更详细地说这句话，所以我不会接受它，但你试过什么？您期望的结果是什么？Thx，双“[”在“[[which（row==1）]”中不是必需的
test <- matrix(c(0,1,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,1,0,0),ncol=5)
colnames(test) <- c('c1','c2','c3','c4','c5')

result <- data.frame(test, result = apply(test, 1, function(row){ if(sum(row)==1)colnames(test)[[which(row==1)]]else 0}))