replacing multiple values in data frame in R

Question

I want to reassign multiple different character strings with the same value in a single call. However, the following code only replaces some of values in each variable.

dat <-data.frame(x=c(rep("1=x",4),rep("b",4)),y=c(rep("1=z",4),rep("b",4)))
dat[] <- sapply(dat[], as.character)
dat[dat == c("1=x", "1=y")]<- 1

such that I get:

dat  
x   y
1   1 1=z
2 1=x 1=z
3   1 1=z
4 1=x 1=z
5   b   b
6   b   b
7   b   b
8   b   b

when I want is the following:

acylam · Accepted Answer · 2018-08-22 17:34:19Z

1

With dplyr:

library(dplyr)

dat <- mutate_all(dat, funs(replace(., grepl("1=", .), 1)))

With Base R:

dat[] <- lapply(dat, function(x) replace(x, grepl("1=", x), 1))

Result:

Data:

dat <- structure(list(x = c("1=x", "1=x", "1=x", "1=x", "b", "b", "b", 
"b"), y = c("1=z", "1=z", "1=z", "1=z", "b", "b", "b", "b")), .Names = c("x", 
"y"), row.names = c(NA, -8L), class = "data.frame")

edited Aug 22, 2018 at 17:34

answered Aug 22, 2018 at 17:27

acylam

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Soeren D. · Accepted Answer · 2018-08-22 17:45:08Z

0

Another Base R option if you want to make an explicit replacement of certain strings would be:

dat[] <- lapply(dat,function(x) ifelse(x %in% c("1=x", "1=z"), 1, x))

Result:

Data:

dat <- structure(list(x = c("1", "1", "1", "1", "b", "b", "b", "b"), 
y = c("1", "1", "1", "1", "b", "b", "b", "b")), row.names = c(NA, 
-8L), class = "data.frame")

answered Aug 22, 2018 at 17:45

Soeren D.

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