[REBOL] Re: count characters. (Was: Simple things should be simple to do ?)
From: brett:codeconscious at: 16-Nov-2000 20:22
> So, let's see if anyone else comes up with even more elegant solutions. I
> love to see other people's code. The ideas some people come up with never
> stop to astound and delight me.
I won't claim my solution to be any more elegant, but just shows another way
of looking at the problem.
I limit my solution to only handling strings and I know at that Rebol at the
moment only has 8bit characters. So I can map characters to array positions.
So the counting part becomes the smallest part of the code and potentially
the fastest bit.
The array structure might be a useful result if you were doing some sort of
batch analysis so I leave it available to be returned using a refinement.
character-count: function [
"Counts characters in a string."
string [string!]
/positional "Return an array of counts - position indicates
character."
] [count-array slot c result-block char-count] [
; Do the counting
count-array: array/initial 256 0
foreach c string [
slot: add 1 to-integer c
poke count-array slot (add 1 pick count-array slot)
]
; Returns the result in desired format
either positional [
RETURN count-array
] [
result-block: copy []
for i 1 256 1 [
if greater? c: pick count-array i 0 [
insert tail result-block reduce [to-char subtract i 1 c]
]
]
RETURN result-block
]
]
Example
>> str: "sdfsdfsdfsdfsdfsd"
== "sdfsdfsdfsdfsdfsd"
>> print mold character-count str
[#"d" 6 #"f" 5 #"s" 6]
Regards
Brett
