R - Replace multiple values in data.frame with one value

Question

I am using R and want to replace multiple values in data.frame starting with certain letters with one value.

For example below is the sample values in my data frame like XYZ1, XYZ2, XYZ3, XYZ4.. etc then i want to replace all values which starts with "XYZ" to "ABC"

Example

df is the data frame

 V1    V2   V3   V4 

XYZ1  XYZ2 XYZ4 XYZ10

XYZ3  RST1 WST3 XYZ11

Here (V1-V4) are the columns on which i want to replace all values which starts with "XYZ" change to "ABC".

Result i want is

df <-

V1   V2   V3   V4 

ABC  ABC  ABC  ABC

ABC  RST1  WST3  ABC

Individually i can do this by using == operator on each value in each column after converting them to character values, but how can i convert all values across multiple columns at once?

Have a look at sub(...)

jogo
– jogo

2018-03-13 14:42:36 +00:00
Commented Mar 13, 2018 at 14:42 — jogo
– jogo, Commented Mar 13, 2018 at 14:42

Nimantha · Accepted Answer · 2021-11-15 05:40:18Z

1

library(dplyr)

df %>%
  mutate_all(funs(gsub("XYZ.*","ABC",.)))
  #mutate_at(vars(V1:V4), funs(gsub("XYZ.*","ABC",.)))

Output is:

   V1   V2   V3  V4
1 ABC  ABC  ABC ABC
2 ABC RST1 WST3 ABC

Sample data:

df <- structure(list(V1 = c("XYZ1", "XYZ3"), V2 = c("XYZ2", "RST1"), 
    V3 = c("XYZ4", "WST3"), V4 = c("XYZ10", "XYZ11")), .Names = c("V1", 
"V2", "V3", "V4"), class = "data.frame", row.names = c(NA, -2L
))

edited Nov 15, 2021 at 5:40

Nimantha

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answered Mar 20, 2018 at 7:52

Prem

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Comments

lemonC · Accepted Answer · 2018-03-13 15:07:17Z

0

Or using gsub

 a <- c("xyz1","xyz9")
    gsub("xyz",x=a,replacement="ABC",ignore.case = FALSE)

answered Mar 13, 2018 at 15:07

lemonC

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2 Comments

Abhinav Sharma Over a year ago

i have a lot of values to be replaced, so it will be tedious work to write down all values, can we do something so that we can select range of columns from where values should be replaced.

lemonC Over a year ago

@AbhinavSharma gsub() is used to capture any certain pattern, in this case any value that contain "XYZ" , and replace that with replacement="ABC. The vector a was just an example I provided to show you how to use gsub. You can certainly use this function inside a loop or using dplyr's mutate as @Prem indicated.

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