[R] Automatically naming subsets in a for loop

2014-01-31 Thread denys
Hello,

I'm trying to subet my data based on long/lat. I have written a for loop
however I am not sure how to get R to name all my subsets different things.
Here is my code so far...

for(i in 0:31){
latl=38+(i*1)
latu=39+(i*1)
for(j in 0:33){
longl=(-72)+(j*1)
longu=(-71)+(j*1)
G$i$j-subset(G, Latlatl  Latlatu  Longlongl  Longlongu)
}
}

However this just freezes my computer. 
Any help is appreciated!



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Re: [R] Automatically naming subsets in a for loop

2014-01-31 Thread Jeff Newmiller
The standard way to do this is to use the cut function to define group 
categories, and then manipulate data in lists of subsets using lapply function 
and relatives. There are also tools such as the plyr package, data.table 
package, sqldf package, and the new dplyr package.

If you want more explicit help, then you really need to read the posting guide 
(e.g. no HTML email), and make a reproducible example (e.g. include some test 
data and an example calculation, even if you have to do it the long way with no 
loops).

http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example
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On January 31, 2014 12:11:04 PM PST, denys de...@uoguelph.ca wrote:
Hello,

I'm trying to subet my data based on long/lat. I have written a for
loop
however I am not sure how to get R to name all my subsets different
things.
Here is my code so far...

for(i in 0:31){
latl=38+(i*1)
latu=39+(i*1)
for(j in 0:33){
longl=(-72)+(j*1)
longu=(-71)+(j*1)
G$i$j-subset(G, Latlatl  Latlatu  Longlongl  Longlongu)
}
}

However this just freezes my computer. 
Any help is appreciated!



--
View this message in context:
http://r.789695.n4.nabble.com/Automatically-naming-subsets-in-a-for-loop-tp4684518.html
Sent from the R help mailing list archive at Nabble.com.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


Re: [R] Automatically naming subsets in a for loop

2014-01-31 Thread jim holtman
Here is one way by just truncating your data to integers based on what
you are doing:

 # create some test data
 n - 1000
 G - data.frame(Lat = runif(n, 38, 50), Long = runif(n, -72, -65))
 # add a 'key' for segment - based on truncating data
 G$key - paste(as.integer(G$Lat), as.integer(G$Long), sep = :)
 # number of unique keys
 length(unique(G$key))
[1] 84
 # split into segments
 segs - split(G, G$key)

 head(G, 20)
Lat  Longkey
1  41.59301 -68.76338 41:-68
2  46.49720 -66.33649 46:-66
3  45.53748 -68.03110 45:-68
4  39.66539 -68.20521 39:-68
5  39.82959 -71.26644 39:-71
6  41.44688 -70.43106 41:-70
7  43.71112 -66.73736 43:-66
8  44.88753 -69.75961 44:-69
9  44.50466 -71.77183 44:-71
10 46.40642 -65.00966 46:-65
11 47.80190 -65.48757 47:-65
12 40.46522 -68.00612 40:-68
13 40.98004 -71.48152 40:-71
14 49.57253 -66.71064 49:-66
15 49.22970 -69.04267 49:-69
16 48.63010 -68.33392 48:-68
17 43.20188 -67.70121 43:-67
18 46.42424 -68.34635 46:-68
19 49.46040 -70.26964 49:-70
20 40.10401 -65.23893 40:-65


Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.


On Fri, Jan 31, 2014 at 3:11 PM, denys de...@uoguelph.ca wrote:
 Hello,

 I'm trying to subet my data based on long/lat. I have written a for loop
 however I am not sure how to get R to name all my subsets different things.
 Here is my code so far...

 for(i in 0:31){
 latl=38+(i*1)
 latu=39+(i*1)
 for(j in 0:33){
 longl=(-72)+(j*1)
 longu=(-71)+(j*1)
 G$i$j-subset(G, Latlatl  Latlatu  Longlongl  Longlongu)
 }
 }

 However this just freezes my computer.
 Any help is appreciated!



 --
 View this message in context: 
 http://r.789695.n4.nabble.com/Automatically-naming-subsets-in-a-for-loop-tp4684518.html
 Sent from the R help mailing list archive at Nabble.com.

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


Re: [R] Automatically naming subsets in a for loop

2014-01-31 Thread denys
Thank you very much !



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http://r.789695.n4.nabble.com/Automatically-naming-subsets-in-a-for-loop-tp4684518p4684524.html
Sent from the R help mailing list archive at Nabble.com.

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and provide commented, minimal, self-contained, reproducible code.