split a string with no spaces to an array?

[anotherJEK]

I want to split a string of ascii characters with no spaces into an array of individual characters.

I looked at the php manual and found that explode() will not accept an
empty string as a delimiter.

So I am trying

PHP Code:

$this->shrtCodeLst = explode(' ', str_replace('', ' ', $this->codeStr));
 print  str_replace('', ' ', $this->codeStr); //testing:  prints string without spaces 


I also look back at the str_replace() entry in the manual and it does not
say anything about empty string for search parameter.
So... Are there any suggestions, inside info, etc here?
I am writing code to generate a captcha graphic and want to apply
some choice to the amount and configuration of the characters in
the string.

Unless I have been blind to a dumb typo, I seem to remember having
done this successfully elsewhere in php v5 code (use empty string as
search parameter in str_replace())

Thanks for time and attention

[Fou-Lu]

PHP Code:

$a = str_split($this->codeStr); 


[anotherJEK]

That rings a bell.