Shell Programming and Scripting

I have a file contents like this....

item1
item2
#item3
item4
#item5
item6
....

I have a KSH script to read this file into an array.
I have a for loop which will read each item...
I want to be able to skip those item start with # sign as first character in a if condiction inside the for loop.

How can I use substr, or parse or whatever way in ksh to detect the first character is a # sign.

Thanks in advance.

grep -v "^#" file.dat | \
while read line
do
echo "Storing into array"
done

Code:

#!/bin/ksh

file='rw.txt'

while read line
do
   (( $(expr "${line}" : '^#') )) && continue;
   echo "line->[${line}]"
done < "${file}"