将NA值替换为0

Question

很抱歉这是我第一次发帖，但我有一个关于更换NA值的问题。该作业声明我必须将"A"的所有值替换为0 所以我尝试了这个命令：

test1[test1 == "A"] <- 0  

但它所做的只是生成NA个值。我尝试使用另一个命令将这些NA值转换为0

test1[is.na(test1)] <- 0  

但我收到"invalid factor level, NA generated"警告。任何帮助将不胜感激。

Answer 1

你的意思是

test1 <- c("A","B","C","A","C")
test1 <- replace(test1, test1=="A", 0)
test1

打印

> test1
[1] "0" "B" "C" "0" "C"

表示数据框：

> test2 <- data.frame(col1 = c("A","B","A"),
+                     col2 = c("D","B","A"),
+                     col3 = c("A","A","X"))
> apply(test2, 1, function(x) {replace(x, x=="A", 0)})
     [,1] [,2] [,3]
col1 "0"  "B"  "0" 
col2 "D"  "B"  "0" 
col3 "0"  "0"  "X" 

并将其转换回data.frame：

as.data.frame(apply(test2, 1, function(x) {replace(x, x=="A", 0)}))