[R-SIG-Finance] Index of data is missing (dim is NULL)
Joshua Ulrich
josh.m.ulrich at gmail.com
Wed Sep 2 13:38:29 CEST 2009
Please use this list for finance-related questions. Just because
you're using R to solve a finance-related problem does not mean your
question is finance-related.
In this case, your "problem" is that rel_data is a *vector*. Please
read, "An Introduction to R" to understand the differences between
vectors and matrices / data.frames (and note that subsetting a matrix
via "[" with drop=TRUE can result in a vector).
> x <- 1:10 # This is a vector
> dim(x)
NULL
> x[1,]
Error in x[1, ] : incorrect number of dimensions
> matrix(1:10,2) # This is a matrix
[,1] [,2] [,3] [,4] [,5]
[1,] 1 3 5 7 9
[2,] 2 4 6 8 10
> matrix(1:10,2)[1,] # This is a vector
[1] 1 3 5 7 9
> matrix(1:10,2)[1,,drop=FALSE] # This is a matrix
[,1] [,2] [,3] [,4] [,5]
[1,] 1 3 5 7 9
HTH,
Josh
--
http://www.fosstrading.com
On Wed, Sep 2, 2009 at 6:26 AM, sunil<sarswat at gmail.com> wrote:
> Hi Users,
> I am working on F&O order-book data, and I noticed index of
> subset of data is missing? Usually when you type the variable name it shows
> you row numbers like [1,], [2,] etc., but here row number is missing. When I
> ask for dim(data) command , it shows "NULL" ? Please see below
>
>> rel_data
> symbols insuments_type expire date quantity price
> time_stamp BS order_type
> "JPASSOCIAT" "FUTSTK" "20080424" "750" "240.90"
> "13:55:30" "S" "RL"
>> dim(rel_data)
> NULL
>> rel_data[1,]
> Error in rel_data[1, ] : incorrect number of dimensions
>>
>
>
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