Recently I have a problme to convert my dataframe. Now I have a data which some columns is the first letter of their name coded as number. For example, Anna coded as 1 due to her first letter of name is "A". Now, I want to change this number to letter in R. Is there any pacakge or tools to help me finshed that? Thanks everyone!

Screenshot of example

I have try to write a function,but it's so inefficient. I have also tried strsplit function, but it can't use in dataframe.

CodePudding user response：

Welcome to StackOverflow! Here is one simple way:

> which("R" == LETTERS) - which("A" == LETTERS)
[1] 17
> 

It takes advantage of

• R having vectors LETTERS and letters
• boolean matching to the letter you look for
• which providing an index
• which we can compute a difference on

(And please do not post links to screenshots or even screenshots. Text is best.)

CodePudding user response：

If you want to change numbers into their correspnding letters in the (English) alphabet:

nmb <- c(1,3,5,2,12,4,20)
LETTERS[nmb]
[1] "A" "C" "E" "B" "L" "D" "T"

LETTERS is a built-in constant in R. If you subset it based on the numbers you want to convert, you will get the corresponding letters.