Shell script - iterate over space separated words/characters (in zsh) - shell

Question

I am having some trouble figuring out how to iterate over space separated words/characters in a shell script. For instance I would like to iterate over a variable containing the characters in the alphabet separated by a space.
NOTE: The result should be the same even if the alphabet variable contained space separated strings instead of characters, i.e "aa bb cc ..." instead of "a b c .."
I have tried a lot of the alternatives provided from:
How to split a line into words separated by one or more spaces in bash?
Example:
local alphabet="a b c d e f g h i j k l m n o p q r s t u v w x y z"
local index="0"
for character in $alphabet; do
index=$((++index))
echo "$index. $character"
# Possibility to do some more stuff
done
Expected/Desired output:
1. a
2. b
3. c
and so on..
Result:
1. a b c d e f g h i j k l m n o p q r s t u v w x y z
Additional tests(without success):
####################################################################
local alphabet="a b c d e f g h i j k l m n o p q r s t u v w x y z"
local index="0"
for character in ${alphabet[#]}; do
index=$((++index))
echo "$index. $character"
# Possibility to do some more stuff
done
####################################################################
local alphabet="a b c d e f g h i j k l m n o p q r s t u v w x y z"
local alphabetArray=( ${alphabet} )
local index="0"
for character in "${alphabetArray[#]}"; do
index=$((++index))
echo "$index. $character"
# Possibility to do some more stuff
done
####################################################################
local alphabet="a b c d e f g h i j k l m n o p q r s t u v w x y z"
local alphabetArray=( ${alphabet} )
local index="0"
for character in ${alphabetArray}; do
index=$((++index))
echo "$index. $character"
# Possibility to do some more stuff
done
Could someone provide a solution on how to solve this(I would prefer a solution that iterates the alphabet variable without explicitly using an index variable, i.e $alphabet[index] )?

Answer 1

Thanks for your help. I discovered the error thanks to your feedback.
I thought that it was irrelevant when I posted this question but I was experimenting with functions in my .zshrc file. Hence I was using (just my assumption) the zsh interpreter and not the sh or bash interpreter.
By realizing that this could be a potential problem, I googled and found the following How to iterate through string one word at a time in zsh
So I tested the following and it works as expected:
setopt shwordsplit
local alphabet="a b c d e f g h i j k l m n o p q r s t u v w x y z"
local index="0"
for character in $alphabet; do
index=$(($index+1))
echo "$index. $character"
# Possibility to do some more stuff
done
unsetopt shwordsplit
NOTE:
index=$((++$index))
and/or
index=$(($index++))
Doesn't seem to work as I expected in zsh.
... The little gritty details, I should have used:
((++index))
or
((index++))
instead of
index=$((++$index))

Answer 2

Try this
IFS=$' \t\n'
local alphabet="a b c d e f g h i j k l m n o p q r s t u v w x y z"
local index="0"
for character in $alphabet; do
index=$((++index))
echo "$index. $character"
# Possibility to do some more stuff
done
Hope it helps