I am using replace function to replace numbers with characters in a list but seem to need to add an extra value to the index list for the code to work. (See example)
Simple version of by problem is that I have a list (0,1) and I want to replace 0 with "a" and 1 with "b".
replace(0:1, 0:1, c("a","b"))
Generates following results
[1] "a" "1"
Warning message:
In x[list] <- values :
number of items to replace is not a multiple of replacement length
when extend index list to 0:2 I get the desired output
> replace(0:1, 0:2, c("a","b"))
[1] "a" "b"
I obviously don't understand how the replace function works but I can't seem to figure out what I am missing.
The second argument to replace is a list of indices (not values) and R uses 1-based indexing. 0:1 only contains 1 valid index. Thus in effect,
replace(0:1, 0:1, c("a","b"))
is equivalent to
replace(0:1, 1, c("a","b"))
which generates the warning message.
It seems that you are really looking for the functionality of mapvalues from the plyr package. For example,
x <- c(2,3,5,7,11)
plyr::mapvalues(x,c(3,7),c(10,12))
which leads to the output:
[1] 2 10 5 12 11
mapvalues is an example of a plyr function that doesn't have a direct analog in the newer package dplyr. See this question. Using both packages simultaneously is not recommended. This is why I used the more explicit plyr::mapvalues() rather than first library(plyr) and then simply mapvalues().