Sum of digits function in Excel and perl. sd(n)

In Excel

From : http://www.listendata.com/2013/02/excel-sum-of-digits-in-number-using-non.html

01. Formula - Sum & Index

Assuming a value is entered in cell B4 i.e. 45454. The sum of the digits of this number is 22.

=SUM(INDEX(1*(MID(B4,ROW(INDIRECT("1:"&LEN(B4))),1)),,))

02. Formula - Sumproduct & Indirect

Assuming a value is entered in cell B4 i.e. 45454. The sum of the digits of this number is 22.

=SUMPRODUCT(MID(B4,ROW(INDIRECT("1:" & LEN(B4))),1)*1)

03. Formula - Sumproduct & Indirect

Assuming a value is entered in cell B4 i.e. 45454. The sum of the digits of this number is 22.

=SUMPRODUCT(MID(B4,ROW(OFFSET($A$1,,,LEN(B4))),1)+0)

04. Formula - Array Formula

For the people who enjoys hitting Ctrl Shift Enter. Assuming a value is entered in cell B4 i.e. 45454. The sum of the digits of this number is 22.

=SUM(MID(B4,ROW(INDIRECT("1:" & LEN(B4))),1)*1)

Note : Press F2 and Hit Ctrl Shift Enter to confirm the above array formula.

In Perl 

sub sd() {

#sum of digits

local $t =0;

        map { $t+= $_; } split //,$_[0];

        return $t;

}

This subroutine splits the first argument $_[0]  into a digits array then adds the elements of the array by maping over the elements.   1234 => 1,2,3,4 => 1+2+3+4 => 10.