Replacing a list value with a string-CodePudding

I have data as follows:

dat <- list(c(0, 25, 100, 250, 500, 1000, 1e 06))

I am simply trying to replace the value 1000000 with the string value "Infinity". Even though:

dat[1]
# [[1]]
# [1]       0      25     100     250     500    1000 1000000

dat[[1]

# [1]       0      25     100     250     500    1000 1000000

If I try:

gsub(1000000, "Infinity", dat[[1]])

Nothing happens. Why does nothing happen in this case and what would be the right way to do this?

CodePudding user response：

You need to assign the RHS gsub call to a LHS variable, probably the vector itself inside the list. But, given that your initial vector contains numerical values, you should instead use equality here:

dat[[1]][dat[[1]] == 1000000] <- "Infinity"
dat

[[1]]
[1] "0" "25" "100" "250" "500" "1000" "Infinity"

CodePudding user response：

We could use rapply. rapply is a recursive version of lapply with flexibility in how the result is structured (how = ".."). See ?rapply

rapply(dat,function(x) ifelse(x==1000000,"Infinity",x), how = "replace")

[[1]]
[1] "0"        "25"       "100"      "250"      "500"      "1000"     "Infinity"

CodePudding user response：

If you really want to use gsub, you need to set fixed = TRUE.

dat <- list(c(0, 25, 100, 250, 500, 1000, 1e 06))

dat[[1]] <- gsub(1000000, "Infinity", dat[[1]], fixed = T)

dat
[[1]]
[1] "0"        "25"       "100"      "250"      "500"      "1000"    
[7] "Infinity"

CodePudding user response：

Another option using replace and lapply (though rapply is the better choice over lapply):

lapply(dat, function(x) replace(x, x == 1000000, "Infinity"))

Output

[[1]]
[1] "0"        "25"       "100"      "250"      "500"      "1000"     "Infinity"