How to mutate few columns depending on certain conditions in R

Question

I have a data frame 'df' as below,

R0 <- c('A','B','C','D','E','F')
R1 <- c(15515.88,5156.04,65656,1566.1,11,56)
R2 <- c(515,5156.11,415,1455,47,335)
R3 <- c(123.14,9875,1247,778.04,1445,6645)
R4 <- c(115.88,56.04,6556,166,545,998)
R5 <- c('XX-XX',"AA-AA","VV-VV","YY-YY", 'XX-XX Component', 'YY-YY Component')
df <- data.frame(R0,R1,R2,R3,R4,R5)

Where I need to multiply R1 to R4 by '-1' if R5's first 5 char are 'XX-XX' or 'YY-YY'. I did the below coding which works fine too,

library(operators) 
d1 <- df2[stringr::str_extract(df2$R5, "^.{5}") %in% c("XX-XX", "YY-YY"),]
d2 <- df2[stringr::str_extract(df2$R5, "^.{5}") %!in% c("XX-XX", "YY-YY"),]

d1[,2:5] <- d1[,2:5]*(-1)
dff <- rbind(d1,d2)

The output is as expected in 'dff', but is there a simple way rather splitting data frames into two and then rbind.

score 4 · Answer 1 · answered Jul 17 '20 at 07:53

4

One dplyr option could be:

df %>%
 mutate(across(R1:R4, ~ if_else(substr(R5, 1, 5) %in% c("XX-XX", "YY-YY"), . * -1, .)))

  R0        R1       R2       R3      R4              R5
1  A -15515.88  -515.00  -123.14 -115.88           XX-XX
2  B   5156.04  5156.11  9875.00   56.04           AA-AA
3  C  65656.00   415.00  1247.00 6556.00           VV-VV
4  D  -1566.10 -1455.00  -778.04 -166.00           YY-YY
5  E    -11.00   -47.00 -1445.00 -545.00 XX-XX Component
6  F    -56.00  -335.00 -6645.00 -998.00 YY-YY Component

answered Jul 17 '20 at 07:53

tmfmnk

38,881
4
47
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I am getting an error, Error: Evaluation error: could not find function "across". Can you suggest? – Vin Jul 17 '20 at 09:10
Did not help, Is it due to the version? I use Version 1.1.383 – Vin Jul 17 '20 at 09:17
1

It should be included from `dplyr` version 1.0.0. – tmfmnk Jul 17 '20 at 09:55

score 2 · Accepted Answer · answered Jul 17 '20 at 07:55

In base R, you can use:

df[2:5] <- df[2:5] * c(1, -1)[grepl('^(XX-XX|YY-YY)', df$R5) + 1]
df
#  R0        R1       R2       R3      R4              R5
#1  A -15515.88  -515.00  -123.14 -115.88           XX-XX
#2  B   5156.04  5156.11  9875.00   56.04           AA-AA
#3  C  65656.00   415.00  1247.00 6556.00           VV-VV
#4  D  -1566.10 -1455.00  -778.04 -166.00           YY-YY
#5  E    -11.00   -47.00 -1445.00 -545.00 XX-XX Component
#6  F    -56.00  -335.00 -6645.00 -998.00 YY-YY Component

We multiply by -1 if R5 starts with XX-XX or YY-YY.

How to mutate few columns depending on certain conditions in R

2 Answers2