CODEWITHSUNDEEP
r
Ravi
Ravi

Reputation: 3303

Replacing elements of a vector

I have the following string:

string <- c("100 this is 100 test 100 string")

I would like to replace the 100's in the above string with elements of another vector:

replacement <- c(1000,2000,3000)

The first 100 of string should be replace by 1000, second 100 by 2000 and so on. The resulting string should look as follows:

result <- c("1000 this is 2000 test 3000 string")

Is there an efficient way to do this in R?

Thank you.

Ravi

Upvotes: 6

Views: 1763

Answers (6)

thelatemail
thelatemail

Reputation: 93813

Late to the party, but regmatches has a regmatches(...) <- value assignment function which allows you to do this sort of thing cleanly in a one liner:

regmatches(string, gregexpr("100",string)) <- list(replacement)
string
# [1] "1000 this is 2000 test 3000 string"

If you don't want to overwrite your original string, you could call the function directly via:

`regmatches<-`(string, gregexpr("100",string), value=list(replacement))
#[1] "1000 this is 2000 test 3000 string"

Upvotes: 2

Nishanth
Nishanth

Reputation: 7130

how about using sub and *apply

tail(sapply(replacement, function(x) {string <<- sub("\\b100\\b",x,string)}), 1)

Upvotes: 0

Rcoster
Rcoster

Reputation: 3210

Another way (need change replacement to a list):

string <- c("100 this is 100 test 100 string")
replacement <- list(1000, 2000, 3000)
result <- do.call(sprintf, c(gsub('100', '%d', string), replacement))

Upvotes: 2

user1317221_G
user1317221_G

Reputation: 15441

one way:

> cs <- strsplit(string," ")[[1]]
> cs[cs == "100"] <- replacement
> cat(cs)
1000 this is 2000 test 3000 string

Upvotes: 3

juba
juba

Reputation: 49033

Here is a way to do it with strsplit :

split <- unlist(strsplit(string, "100", fixed=TRUE))
split <- split[nchar(split) > 0]
paste0(replacement, split, collapse="")
# [1] "1000 this is 2000 test 3000 string"

The second line is here because strsplit add an empty string at the beginning of its results because 100 appears in the first position.

Upvotes: 1

CHP
CHP

Reputation: 17189

Not very elegant, but this should do..

string <- c("100 this is 100 test 100 string")
temp <- unlist(strsplit(string, split = "\\s+"))
replacement <- c(1000, 2000, 3000)
temp[temp == "100"] <- replacement
result <- paste(temp, collapse = " ")

result
## [1] "1000 this is 2000 test 3000 string"

Upvotes: 2

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