[R] data frame: adding columns from data and file title

[Rui Barradas]

Hello,

First of all, the best way of posting data examples is ?dput. Anyway, 
try the following.



dat <- read.table(text="
Date_ Time_ Speed  Course  Type_  Distance
30/03/2012  11:15:05  108  121  -2 0
30/03/2012  11:15:06    0   79   0 0
30/03/2012  11:15:07    0   76   0 1
30/03/2012  11:15:08    0   86   0 2
30/03/2012  11:15:09    0   77   0 3
", header = TRUE, stringsAsFactors = FALSE)
dat
str(dat)


filename <- "G7_pig328_unit328_Site141_30MAR2012_RNo4_SitNo1.csv"

dat$cDistance <- cumsum(dat$Distance)
x <- unlist(strsplit(filename, "_"))[1:2]
x <- as.integer(sub("[[:alpha:]]+", "", x))
dat$Group <- x[1]
dat$BIRD <- x[2]
dat


Hope this helps,

Rui Barradas
Em 28-11-2012 09:33, jgui001 escreveu:
> Data processing”
>
> I have a large number of csv files from animal tracks that look like this:
>
> Date_	                              Time_		                      Speed		
> Course	                      	Type_		                      Distance
> 30/03/2012	                      11:15:05		                      108		
> 121	                   	                         	-2		
> 0
> 30/03/2012	                      11:15:06		                      0		
> 79		               	                             0		                      0
> 30/03/2012		                      11:15:07		                      0		
> 76	                  	                          	0		                      1
> 30/03/2012		                      11:15:08		                      0		
> 86		               	                             0	                      	2
> 30/03/2012		                      11:15:09		                      0		
> 77		                	                            0		                      3
>
> Each file has a name like this
> “G7_pig328_unit328_Site141_30MAR2012_RNo4_SitNo1.csv”
>
> To automate the processing I would like to
> 1. Add on various columns calculated from within the data frame e.g.
> cumulative distance traveled (cDistance) by Summing the distance column from
> [1 :n] for each row
> 2 Add columns derived from the file name so when I merge all the files
> together I know what observation corresponds to which group and bird etc.
> For example G7 stands for group 7, pig328 is pigeon328:
>
> The file look the same with but with these columns (plus others) added
>
> cDistance		                      Group	      	BIRD
> 0                        	                       	7		      328
> 0	                    	                          7		      328
> 1	                    	                          7		      328
> 3	                     	                         7		      328
> 6	                    	                         7		      328
>
> I was thinking a function like this for cDistance (if I can get it to work)
>
> cdistamce <-funtion(x){
>     i = 1
>     j=nrow(temp1.df)
>    while(i<=j,ifelse(i=1,"Distance[i]",Sum("Distance"))
>          i=i+1
> }
>
> But hit a brick wall and I have no idea about adding columns from the name.
> Am I on the right track with the first one and any ideas, coz I can't brain
> today I have the dumb!?
>
> Cheers
> Josh
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/data-frame-adding-columns-from-data-and-file-title-tp4651099.html
> Sent from the R help mailing list archive at Nabble.com.
>
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