CODEWITHSUNDEEP
rdataframemax
Codezy
Codezy

Reputation: 662

How to give value to the one which is not equal to max value in each row?

I have a data frame which contains some values. And now I would like to keep only the max value in each row and give 0 to the rest column, like this:

df <-  data_frame(a= c(1,2,3,4,5),b= c(2,5,3,9,7),c= c(40,6,2,1,7))
df$rowmax <- apply(df,1,max)
#
      a     b     c rowmax
  <dbl> <dbl> <dbl>  <dbl>
     1     2    40     40
     2     5     6      6
     3     3     2      3
     4     9     1      9
     5     7     7      7
#ideal out put
     a     b     c    rowmax
     0     0     40    40
     0     0     6     6
     3     3     0     3
     0     9     0     9
     0     7     7     7

Could any one help me out here? thanks ; )

Upvotes: 2

Views: 191

Answers (2)

arg0naut91
arg0naut91

Reputation: 14774

A base option:

sweep(df, 1, apply(df, 1, max), FUN = function(x, y) x * (x == y))

Output:

  a b  c
1 0 0 40
2 0 0  6
3 3 3  0
4 0 9  0
5 0 7  7

Upvotes: 2

akrun
akrun

Reputation: 887891

It may be more efficient to use pmax to get the row wise max, then select the columns of interset in mutate_at and replace the values in each column not equal to 0

library(dplyr)
library(purrr)
df %>% 
   mutate(rowmax = reduce(., pmax)) %>% 
   #or as  @tmfmnk mentioned in the comments
   # mutate(rowmax = exec(pmax, !!!.)) %>%
   mutate_at(vars(a:c), ~ replace(., .!= rowmax, 0))
   #Or do a multiplication
   #mutate_at(vars(a:c), ~. * (.== rowmax))

Also, if we don't need the rowmax column, a base R option is

df * (df == do.call(pmax, df))

Upvotes: 3

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