Displaying 2 results from an estimated 2 matches for "sddensiti".
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sddensity
2012 Apr 05
2
count() function
I keep expecting R to have something analogous to the =count function in
Excel, but I can't find anything. I simply want to count the data for a
given category.
I've been using the ddply() function in the plyr package to summarize
means and st dev of my data, with this code:
ddply(NZ_Conifers,.(ElevCat, DataSource, SizeClass), summarise,
avgDensity=mean(Density),
2012 Mar 25
2
avoiding for loops
I have data that looks like this:
> df1
group id
1 red A
2 red B
3 red C
4 blue D
5 blue E
6 blue F
I want a list of the groups containing vectors with the ids. I am
avoiding subset(), as it is
only recommended for interactive use. Here's what I have so far:
df1 <- data.frame(group=c("red", "red", "red", "blue",