[R] using zoo for daily stock prices

[Alfonso Sammassimo]

Hi all,

Please forgive this newbie posting to the list for the first time if I 
haven't followed proper procedure. I have read through many of the archives 
and find them most useful in learning R.

I have ten years daily data (stock closing prices) which I read in zoo 
format. I am having problems coding R to run a count of how many days in 
each month have a price higher than the first day of that month. I then wish 
to compare counts for all months. Along these lines, is there a simple way 
to index to certain dates(eg first of month, last of month, any specific 
date in one month) and keep looping over each month using such a reference 
point, and then assessing the results for each month?

Any guidance would be sincerely appreciated,

Alfonso Sammassimo
Melbourne, Australia.