Dear All, I am struggling with a simple problem. I did some online research, but I am still banging my head against the floor. I read a csv file into a data frame and I have a columns with entries like 2012-04-13 00:23:45 2012-04-22 07:53:09 etc.. Each line posted above is the content of a single cell. How can I convert that into Unix time? Many thanks Lorenzo