(50G) Digits sum (50g)

[John Keith]

I was going to post about I->NL but you beat me to it.

Also I->BL for bases other than 10.

For integers up to 100 digits or so, I->NL LSUM is fastest. For numbers larger than 100 digits, this strange program is actually faster:

Code:


\<<
  \->STR 0 SWAP 1. 9.
    FOR j j 48. + CHR "" SREPL j * ROT + SWAP
    NEXT DROP
\>>

SREPL is crazy fast, I have used it for lots of odd purposes like this.

Here is a similar program that returns a list of 10 numbers which are the counts of each digit from 1 to 9 in a large integer:

Code:


\<< 
   \->STR 48. 57.
    FOR j j CHR "" SREPL SWAP
    NEXT DROP 10. \->LIST
\>>

For integers less than 70 digits or so, I\->NL LSORT LRPCT is faster (and a lot shorter).