r - return number of specific element of vector based of its name -

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• convert letters numbers 5 answers

i need return number of element in vector based on vector element name. lets have vector of letters:

myletters=letters[1:26] > myletters  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x" "y" "z" 

and intent create/find function returns me number of element when called example:

myfunction(myletters["b"]) [1] 2  myfunction(myletters["z"]) [1]26 

in summary need way refer excel columns writing letters of column (a,b,c later maybe aa or further) , number.

if want refer excel columnnames, create reference vector possible excel column names:

eg1 <- expand.grid(letters, letters) eg2 <- expand.grid(letters, letters, letters) excelcols <- c(letters, paste0(eg1[[2]], eg1[[1]]), paste0(paste0(eg2[[3]], eg2[[2]], eg2[[1]]))) 

after can use which:

> which(excelcols == 'a') [1] 1 > which(excelcols == 'ab') [1] 28 > which(excelcols == 'abc') [1] 731