Emacs Lisp: getting ascii value of character

Question

I'd like to translate a character in Emacs to its numeric ascii code, similar to casting char a = 'a'; int i = (int)a in c. I've tried string-to-number and a few other functions, but none seem to make Emacs read the char as a number in the end.

What's the easiest way to do this?

Answer 1

A character is a whole number in Emacs Lisp. There is no separate character data type.

Function string-to-char is built-in, and does what you want. (string-to-char "foo") is equivalent to (aref "foo" 0), which is @abo-abo's answer --- but it is coded in C.

Answer 2

String is an array.

(aref "foo" 0)

Answer 3

To get the ascii-number which represents the character --as Drew said-- put a question mark before the character and evaluate that expression

?a ==> 97

Number appears in minibuffer, with C-u it's written behind expression.

Also the inverse works

(insert 97) will insert an "a" in the buffer.

BTW In some cases the character should be quoted

?\" will eval to 34