[R] Length of data.frame column

[rkevinburton at charter.net]

I have a beginner question. After I finally get the data to a data.frame that I can work with I have the following a data frame that is fairly long:

> length(r2007)
[1] 17409

If I look at the first element:

> r2007[1]
$`100009`
  DayOfYear Quantity
1        66        1
2       128        1
3       137        1
4       193        1

Now how do I get the length of this list (actually it is another data.frame)?

I have tried:

> length(r2007[1])
[1] 1

Not right. And:

> length(r2007[1]$DayOfYear)
[1] 0

Also not right the length returned should be 4 from the output above. I want to use this to iterate through the object. So in the outer loop I would have:

for(i in 1:length(r2007))
{
. . . .
}

I need to form an inner loop and an expression that returns each row (as above).

Any ideas?

Thank you.

Kevin