r - 用数字替换字符

Question

很抱歉打扰你。我有一个 data.frame 包含以下项目：

F1008Y
F1008Y
406_407insD
R1207*

我想用“1”替换所有这些项目。如何做到这一点？

Answer 1

您可以使用ifelse

DF <- read.table(text="F1008Y
F1008Y
406_407insD
R1207*
0
0", header=FALSE) # adding some 0

DF # this is your data.frame
           V1
1      F1008Y
2      F1008Y
3 406_407insD
4      R1207*
5           0
6           0

ifelse({df <- DF; df!=0}, df[,] <- 1, df[,] <- 0) # replacing
     V1
[1,]  1
[2,]  1
[3,]  1
[4,]  1
[5,]  0
[6,]  0

 # the original data.frame remains the same
 DF
           V1
1      F1008Y
2      F1008Y
3 406_407insD
4      R1207*
5           0
6           0

Answer 2

这是一个利用以下事实的示例：当您as.numeric在将数字和字符串混合在一起的向量上使用时，字符串会转换为NA. 我添加了一个额外的专栏只是为了好玩。

DF <- read.table(text="F1008Y
F1008Y
406_407insD
R1207*
0
0", header=FALSE)
DF$V2 <- DF$V1
DF.bak <- DF ## Backups are always nice
DF
#            V1          V2
# 1      F1008Y      F1008Y
# 2      F1008Y      F1008Y
# 3 406_407insD 406_407insD
# 4      R1207*      R1207*
# 5           0           0
# 6           0           0
## By default, the columns have been read in as factors. Convert to character
DF[sapply(DF, is.factor)] = lapply(DF[sapply(DF, is.factor)], as.character)
DF[is.na(sapply(DF, as.numeric))] <- 1
# Warning messages:
# 1: In lapply(X = X, FUN = FUN, ...) : NAs introduced by coercion
# 2: In lapply(X = X, FUN = FUN, ...) : NAs introduced by coercion
DF
#   V1 V2
# 1  1  1
# 2  1  1
# 3  1  1
# 4  1  1
# 5  0  0
# 6  0  0