I have the following backtick on my list's names. Prior lists did not have this backtick.
$`1KG_1_14106394`
[1] "PRDM2"
$`1KG_20_16729654`
[1] "OTOR"
I found out that this is a 'ASCII grave accent' and read the R page on encoding types. However what to do about it ? I am not clear if this will effect some functions (such as matching on list names) or is it OK leave it as is ?
Encoding help page: https://stat.ethz.ch/R-manual/R-devel/library/base/html/Encoding.html
Thanks!
My understanding (and I could be wrong) is that the backticks are just a means of escaping a list name which otherwise could not be used if left unescaped. One example of using backticks to refer to a list name is the case of a name containing spaces:
lst <- list(1, 2, 3)
names(lst) <- c("one", "after one", "two")
If you wanted to refer to the list element containing the number two, you could do this using:
lst[["after one"]]
But if you want to use the dollar sign notation you will need to use backticks:
lst$`after one`
Update:
I just poked around on SO and found this post which discusses a similar question as yours. Backticks in variable names are necessary whenever a variable name would be forbidden otherwise. Spaces is one example, but so is using a reserved keyword as a variable name.
if <- 3 # forbidden because if is a keyword
`if` <- 3 # allowed, because we use backticks
In your case:
Your list has an element whose name begins with a number. The rules for variable names in R is pretty lax, but they cannot begin with a number, hence:
1KG_1_14106394 <- 3 # fails, variable name starts with a number
KG_1_14106394 <- 3 # allowed, starts with a letter
`1KG_1_14106394` <- 3 # also allowed, since escaped in backticks
