title: Time series data format
body: <p>I'm a beginner in working with R. In general I do have csv files which I'm gonna read with "read.csv".
  The files have 2 colums: </p>
  
  <p>1st is date: "2013-01-01 22:20:00"</p>
  
  <p>2nd is value: 0 </p>
  
  <p>So far I just took the var$2nd for analysis on data - but I need the date. Is it possible to read this date? And ask for the values between two dates? Or exclude values always between two times?
  What is the right data format, how to convert and which is standard if I just read.csv</p>
  
  <p>Thank you!</p>