Get the alphabetical colnames corresponding to numbers (indices)

Source: R/makeXlColAlphabet.r

This function supports nchar up to 4 (ZZZZ), i.e. the upper limit of number is 475,254.

index2abc(num, nchar = 4L)

Arguments

num

an integer vector which is converted to alphabets.

nchar

an integer used for creating an alphabetical name base. Default: 4L.

Value

a character vector

Examples

index2abc(num = 5)        # "E"
#> [1] "E"
index2abc(num = 10^(1:5)) # "J" "CV" "ALL" "NTP" "EQXD"
#> [1] "J"    "CV"   "ALL"  "NTP"  "EQXD"
if (FALSE) {
 index2abc(num = 500000)   # Error. due to exceeding sum(26^(1:4))
}