I am trying to create a column of characters based on an existing column of numbers, preferably without using a `for`

loop. I have come up with a variety of ways to do this, but I keep feeling like I'm making this far more complicated than it needs to be.

Here is the dreaded and time-consuming `for`

loop version *(edited)*:

```
joe <- as.data.frame(matrix(round(runif(10,1,5),0),nrow=10,ncol=1))
chr <- function(n) { rawToChar(as.raw(n)) }
m = ncol(joe)+1
for (i in 1:nrow(joe)){
joe[i,m] <- chr(joe[i,m-1]+64)
}
joe
V1 V2
1 2 B
2 1 A
3 3 C
4 2 B
5 1 A
6 3 C
7 2 B
8 5 E
9 3 C
10 4 D
```

Yeah. That works. As expected. But for a real dataset, that operation will take a very long time.

How about using an ASCII conversion function like rawToChar?

```
joe <- as.data.frame(matrix(round(runif(10,1,5),0),nrow=10,ncol=1))
joe[,ncol(joe)+1] <- rawToChar(as.raw(64+joe[,1]))
joe
V1 V2
1 1 ACCAACACDC
2 3 ACCAACACDC
3 3 ACCAACACDC
4 1 ACCAACACDC
5 1 ACCAACACDC
6 3 ACCAACACDC
7 1 ACCAACACDC
8 3 ACCAACACDC
9 4 ACCAACACDC
10 3 ACCAACACDC
```

That totally didn't work. The output of rawToChar isn't a vector, but a string. Is there anything that takes vector numeric input and outputs a character list?

Abandoning that approach for a bit, I was able to get two other ways to work... but they aren't particularly elegant, taking quite a few lines of code to implement. First the lookup table approach:

```
library("dplyr")
grades <- as.data.frame(matrix(seq(1,5,by=1),nrow=5,ncol=1))
grades <- cbind(grades, c("A","B","C","D","E"))
colnames(grades) <- c("num","ltr")
joe <- as.data.frame(matrix(round(runif(10,1,5),0)),nrow=10,ncol=1)
colnames(joe) <- c("num")
left_join(joe, grades, by="num")
num ltr
1 3 C
2 4 D
3 2 B
4 5 E
5 4 D
6 2 B
7 2 B
8 1 A
9 5 E
10 2 B
```

And now using factors and levels:

```
joe <- as.data.frame(matrix(round(runif(10,1,5),0)),nrow=10,ncol=1)
joe$V2 <- as.factor(joe$V1)
levels(joe$V2) <- c("A","B","C","D","E")
joe$V2 <- as.character(joe$V2)
joe
V1 V2
1 4 D
2 1 A
3 3 C
4 2 B
5 3 C
6 3 C
7 5 E
8 2 B
9 4 D
10 4 D
```

So my question is really... are there other simpler and more elegant ways of doing this that I haven't thought of yet? Because it sure seems like I have invented some pretty complex ways to do a pretty simple operation.

Thanks in advance for your input.