[R] Filling a grid based on existing data

[David Winsemius]

On Mar 25, 2010, at 7:01 AM, Steve Murray wrote:

>
> Sorry, that was a poorly worded question. You're right in that the  
> gaps are in fact NAs and I would be proposing to remove these  
> entirely. So it's really a case of filling up a 720 x 360 grid (by  
> row) based on the data in the 18556 rows x 19 columns data frame.
>
> I've tried doing:

Had I been planning on using the vector-nature of matrices in R, and  
rearranging by altering the dimension attribute,  I would ahve  
converted the original dataframe to a matrix using the data.matrix  
function and then done the assignment to data_mat as you propose.

so try this:

d_inter <- data.matrix(data)

data_mat <- matrix(d_inter, nrow=360, ncol=720, byrow=TRUE)

-- 
David.

> Warning message:
> In matrix(river, nrow = 360, ncol = 720, byrow = TRUE) :
>   data length [19] is not a sub-multiple or multiple of the number  
> of rows [360]
>
> But this results in a mess!
>
>  head(data_mat)
>      [,1]          [,2]          [,3]          [,4]          [,5]
> [1,] Numeric,18556 Numeric,18556 Numeric,18556 Numeric,18556 Numeric, 
> 18556
> [2,] Numeric,18556 Numeric,18556 Numeric,18556 Numeric,18556 Numeric, 
> 18556
> [3,] Numeric,18556 Numeric,18556 Numeric,18556 Numeric,18556 Numeric, 
> 18556
> [4,] Numeric,18556 Numeric,18556 Numeric,18556 Numeric,18556 Numeric, 
> 18556
> [5,] Numeric,18556 Numeric,18556 Numeric,18556 Numeric,18556 Numeric, 
> 18556
> [6,] Numeric,18556 Numeric,18556 Numeric,18556 Numeric,18556 Numeric, 
> 18556
>
>
> If it's of any use, the original data are structured as follows:
>
> str(data)
> 'data.frame':   18556 obs. of  19 variables:
>  $ V1 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V2 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V3 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V4 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V5 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V6 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V7 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V8 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V9 : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V10: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V11: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V12: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V13: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V14: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V15: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V16: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V17: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V18: num  0 0 0 0 0 0 0 0 0 0 ...
>  $ V19: num  0 0 0 0 0 0 0 0 0 0 ...
>
>
> Don't worry about all the zeros - there are plenty of greater values  
> later on!
>
> Any help would be gratefully received. Thanks,
>
> Steve
>
>
> ----------------------------------------
>> From: dwinsemius at comcast.net
>> To: smurray444 at hotmail.com
>> Subject: Re: [R] Filling a grid based on existing data
>> Date: Wed, 24 Mar 2010 20:50:40 -0400
>>
>>
>> On Mar 24, 2010, at 2:34 PM, Steve Murray wrote:
>>
>>>
>>> Dear all,
>>>
>>> I currently have a data frame of dimensions 18556 rows by 19
>>> columns. I want to convert this into a grid of dimensions 720 rows
>>> by 360 columns. The problem in this case is that not all rows in the
>>> initial data frame are complete (there are gaps).
>>>
>>> Therefore I am perhaps looking for a way of filling a 720 x 360 grid
>>> by reading in all values in each row until one is encountered which
>>> does not have 19 columns. In these cases, the row in the new grid
>>> should be filled (as the gaps occur every 720 values), and filling
>>> should re-start on the next row of the new grid. I hope this is
>>> reasonably clear!
>>
>> Perhaps it could become clearer. Dataframes in R do not have "gaps".
>> They may have NA's but all the columns and rows have _something_.
>> And ... with what were you proposing to Fill these "gaps".
>>
>> --
>> David
>>
>>>
>>> Many thanks for any help,
>>>
>>> Steve
>>>
>>>
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>>
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