I have a vector of character strings

```
vec <- c("1ZQOYNBAA55", "2JSNHGKLRBB66", "3HVXCC77", "4LDD88", "5CIFMTLYXEE99")

> vec
[1] "1ZQOYNBAA55"   "2JSNHGKLRBB66" "3HVXCC77"      "4LDD88"        "5CIFMTLYXEE99"

```

...and I would like to get the last 3 characters from each string. To get the first 3 characters, I can use `substr()`

```
substr(vec,1,3)

```

I would have thought something like `substr()` with a "fromLast" argument might exist

```
vec_ends <- substr(vec,1,3, fromLast = TRUE)

```

With an expected output

```
> vec_ends
[1] "A55" "B66" "C77" "D88" "E99"

```

But `substr()` only works one way. In my dataset the string lengths are variable so no reference to absolute character numbers or string lengths can be made, and there are no consistent separators of delimiting characters for a string split. Does anyone know of an easy way to do this in R?