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### Re^5: How to split an integer??

by tobyink (Abbot)
 on Dec 06, 2012 at 11:40 UTC ( #1007540=note: print w/replies, xml ) Need Help??

in reply to Re^4: How to split an integer??
in thread How to split an integer??

"23 s stored as a single byte hence i cant split."

Byte?! You're thinking in C terms! Go wash your mouth out with soap right now! ;-)

In Perl, strings and integers are both represented by the same data type - scalars. (Internally Perl represents scalars as a C struct which has separate string and integer slots. But you don't normally need to worry about such concerns.) If you have a variable that contains an integer value, such as 23, and pass it to something that expects a string, like split, that integer will be silently converted to a string.

Here's exactly the same function I posted before, only now I'm using the integer 23 as the input...

```use 5.010;
use strict;
use warnings;

# 23 is an integer.
#
say digit_sum(23);

# This expression is used to test that a string consists of a single
# digit. We use it a couple of different places, so we'll get define
# it once here.
#
use constant DIGIT => qr/^[0-9]\$/;

# This is the function which adds digits
#
sub digit_sum {
my \$string = shift;

# Otherwise, split into digits.
my @digits =
grep { \$_ =~ DIGIT }  # keep only the numeric characters
split '', \$string;    # split into characters

my \$sum = 0;
\$sum += \$_ for @digits;

# Handle the trivial case.
# If \$sum is just a single digit, return it as-is.
return \$sum if \$sum =~ DIGIT;

# Otherwise, recurse.
return digit_sum(\$sum);
}
perl -E'sub Monkey::do{say\$_,for@_,do{(\$monkey=[caller(0)]->[3])=~s{::}{ }and\$monkey}}"Monkey say"->Monkey::do'

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