Question

我有一个带数值的data.frame。如何用0替换每行最大值例如，连续一行：

10,1,3,4

输出将是

0,1,3,4

我试过了：

df1  <- data.frame(df)[apply(df,1,which.max=0)]

但我有些不对劲。

我很感激你的帮助。

Answer 1

怎么样

replace_max <- function(x){x[which.max(x)] <- 0;x}

t(apply(df, 1, replace_max))

或

library(plyr)
adply(df, 1, replace_max)

编辑来做行

编辑：2 以确保data.frame

Answer 2

我将如何做到这一点：

a <-matrix(round(runif(25)*100,0),ncol=5) #create matrix
my.max <-apply(a,1,which.max) #find max position by row

>     a
     [,1] [,2] [,3] [,4] [,5]
[1,]   62   14   19   64   40
[2,]   74   83   26   95   14
[3,]   32   69   24   12   67
[4,]  100   57   19    3   16
[5,]   41    6   93   85   67


z <-cbind(1:5,my.max) #create coordinates
a[z] <-0 #replace those entries
>     a
     [,1] [,2] [,3] [,4] [,5]
[1,]   62   14   19    0   40
[2,]   74   83   26    0   14
[3,]   32    0   24   12   67
[4,]    0   57   19    3   16
[5,]   41    6    0   85   67

Answer 3

试试这个：

#Generating a fake dataframe:
   df=data.frame(A=c(1:5), B=c(6,111,5,7,10), C=c(11,28,65,7,15) , D=c(21:25))
 > df
  A   B  C  D
1 1   6 11 21
2 2 111 28 22
3 3   5 65 23
4 4   7  7 24
5 5  10 15 25

n=length(rownames(df))
for(i in 1:n){
c1=as.numeric(which.max(df[i,]))
df[i,c1]=0

}


df    #output
   A  B  C  D
 1 1  6 11  0
 2 2  0 28 22
 3 3  5  0 23
 4 4  7  7  0
 5 5 10 15  0

Answer 4

怎么样：

x <- matrix(sample(1:16),nrow=4)

x
     [,1] [,2] [,3] [,4]
[1,]    1   12    6    4
[2,]   16    2   13   15
[3,]   11    8   10    7
[4,]   14    9    5    3

x*as.logical(x-apply(x,1,max))
     [,1] [,2] [,3] [,4]
[1,]    1    0    6    4
[2,]    0    2   13   15
[3,]    0    8   10    7
[4,]    0    9    5    3

用0替换最大行

4 个答案: