title: Searching a Data Frame in R
body: <p>How do I go about searching a <code>data.frame</code> based on multiple criteria? For instance, I have a <code>data.frame</code> with columns such as <code>Date</code>, <code>Time</code>, <code>Item</code>, <code>Value</code>, and I then want to search the <code>data.frame</code> where I have <code>Date = 1/2/2010</code>, <code>Time = 5pm</code>, <code>Item = Car</code>, <code>Value = 5</code>, is there a function that will allow me to do that? More importantly, how do I obtain the row index of the data frame which has these values?</p>
  
  <p>For example, say all these values are in the third row of the data frame, is there a function which will search the data frame row by row and then output that index is 3?</p>