I want the slope from a couple of columns that looks like so:

```
date    time
7/8/2014    23.4917166
7/9/2014    28.69671107
7/10/2014   27.3262166
7/11/2014   30.25426663
7/12/2014   29.8345944
7/13/2014   27.7473055
7/14/2014   29.8657722
7/15/2014   29.2622055

```

The problem is, lm() doesn't seem to play ball with date in a mm/dd/yyyy format. If I make the date data numeric like so:

```
date    time
1   23.4917166
2   28.69671107
3   27.3262166
4   30.25426663
5   29.8345944
6   27.7473055
7   29.8657722
8   29.2622055

```

and run something like

```
timetest <- read.table("clipboard", sep="\t", header=T)
test <- lm(time ~ date, data=timetest)
coefficients(test)[2]

```

I get:

```
    date 
0.5605038 

```

So how should I go about transforming the mm/dd/yyyy date format into something numeric? Is there a function to cast them as unix time?