Hi all, 
  Firstly I appologise if this question has been answered previously,
however searching of the archives and the internet generally has not
yielded any results. 
 
  I am looking in to the effects of summer weather conditions
(temperature, humidity etc), on the incidences of a breathing disorder
brought on through smoking (COPD). I am fairly new to R and completely
new to the idea of writing R scripts, subsetting dataframes etc. I am
working on a 12 week summer placement at the Met Office, UK, having just
finished my second year of a mathematics course at university. 
 
  Basically I have data between January 1 1997 and December 31 2007.
However as I am only interest in the summer months (which I have defined
to be between May 1 and September 30), I would like to extract the
relevant data in R in a timely manner. Obviously I could go and open my
csv files in excel, cut and paste the relevant data, etc, however I
would like to maximise R's potential as I feel it will stand me in
better stead in the long run. 
  Currently the dates are in the form 
1-Apr-1997,
3-Sept-2001,
etc. 
  I will create a data.frame with date as one of the variables, the
others being (initially) temperature, humidity, and Admissions (the
number of hospital admissions for COPD exaserbations). 
  Please could somebody tell me if there is a simple way to extract the
data I want, and if so perhaps a sample command to get me going? Do I
first need to format the dates to some numeric-only format? As I say, I
could use Excel to create the files in the right format, but I will be
dealing with a lot more variables in the future (perhaps up to 8) and so
this will become a pain-staking process. 
 
  Please reply either on or off list.
 
Many thanks for any help.       
Robin Williams
Met Office summer intern - Health Forecasting
robin.williams@metoffice.gov.uk 
 

	[[alternative HTML version deleted]]

