[R] Reading a data file one record at a time [SEC=UNCLASSIFIED]

[jim holtman]

try this:

> input <- readLines(textConnection("header line
+ Ray1 header
+ gate1 1,2,3,4,5,6,7
+ gate2 5,6,7,8,9,0
+ Ray2 header
+ gate1 5,4,3,2,1
+ gate2 8,7,6,5,4,34"))
> closeAllConnections()
> # delete first header line
> input <- input[-1]
>
> # read the data one line at a time, parsing the data
> result <- list()
> for (line in input){
+     # strip leading blanks
+     line <- sub("^ *", "", line)
+     x <- strsplit(line, ' ')[[1]]
+     if (x[2] == 'header'){
+         key <- x[1]  # save 'Rayn' as key to data
+         next
+     }
+     result[[key]][x[1]] <- list(as.numeric(strsplit(x[2], ',')[[1]]))
+ }
>
> result
$Ray1
$Ray1$gate1
[1] 1 2 3 4 5 6 7

$Ray1$gate2
[1] 5 6 7 8 9 0


$Ray2
$Ray2$gate1
[1] 5 4 3 2 1

$Ray2$gate2
[1]  8  7  6  5  4 34




On Thu, Nov 12, 2009 at 1:02 AM, Justin Peter <J.Peter at bom.gov.au> wrote:
> Dear r-help,
>
> I have a radar data file in the following format:
>
> nrays
> for (1 to n_rays)
> { some_data_info
>  for (1 to n_gates)
>  { some_data_info}
> }
>
> N_rays=360 and n_gates=950
>
> The data looks something like:
>
>    Header line1
>    Ray1 header
>        gate1 var1, var2,.....,varN
>        ...
>        gate950 var1, var2,.....,varN
>    Ray2 header
>        gate1 var1, var2,.....,varN
>        ...
>        gate950 var1, var2,.....,varN
>    ...
>    ...
>    ...
>   Ray360 header
>       gate1 var1, var2,.....,varN
>        ...
>       gate950 var1, var2,.....,varN
>
> I am having trouble reading this data. Are there any suggestions on how to read the data file one block (corresponding to one ray) at a time?
>
> Any help appreciated.
>
> Regards,
> Justin
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Justin R. Peter
> Research Scientist
> Queensland Climate Change Centre of Excellence
> based at
> Centre for Australian Weather and Climate Research (CAWCR),
> A partnership between the Australian Bureau of Meteorology and CSIRO
>
> e: j.peter at bom.gov.au<mailto:j.peter at bom.gov.au>
> p: +61 (0) 3 9669 4838
> f: +61 (0) 3 9669 4660
> s: Level 9
> Bureau of Meteorology Building
> 700 Collins Street
> Docklands
> VIC 3008
> Australia
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
>        [[alternative HTML version deleted]]
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?