Question

In Python, I can do this:

>>> import string
>>> string.letters
'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

Is there any way to do something similar in Clojure (apart from copying and pasting the above characters somewhere)? I looked through both the Clojure standard library and the java standard library and couldn’t find it.

Answer 1

A properly non-ASCII-centric implementation:

private static String allLetters(String charsetName)
{
    CharsetEncoder ce = Charset.forName(charsetName).newEncoder();
    StringBuilder result = new StringBuilder();
    for(char c=0; c<Character.MAX_VALUE; c++)
    {
        if(ce.canEncode(c) && Character.isLetter(c))
        {
            result.append(c);
        }
    }
    return result.toString();
}

Call this with “US-ASCII” and you’ll get the desired result (except that uppercase letters come first). You could call it with Charset.defaultCharset(), but I suspect that you’d get far more than the ASCII letters on most systems, even in the USA.

Caveat: only considers the basic multilingual plane. Wouldn’t be too hard to extend to the supplementary planes, but it would take a lot longer, and the utility is questionable.