Repeat elements of matrix based on vector counts
Hi Sarah, If I understand your requirements correctly, the easiest thing to do is approach it from a different direction: df3a <- merge(df1, df2) But you can also use rep for this simple example because plot.id in df2 is sorted: nindex <- table(df1$plot.id) df3b <- df2[rep(1:length(nindex), times=nindex),] Thanks for the reproducible example, Sarah
On Thu, Dec 13, 2012 at 9:15 AM, Sarah Haas <haaszoology at gmail.com> wrote:
I have two dataframes (df) that share a column header ("plot.id"). In the
1st df, "plot.id" records are repeated a variable number of times based on
the number of trees monitored within each plot. The 2nd df only has a
single record for each "plot.id", and contains a variable named "load" that
is collected at the plot-level and is only listed once per plot record.
*OBJECTIVE:* I need to repeat the "load" values from the 2nd df based on
how many times "plot.id" is repeated in the 1st df (all plots are repeated
a different number of times). My example dfs are below:
************************************************************************************************
df1 <- data.frame(plot.id = rep(c("plot1", "plot2", "plot3"),
c(3,2,5)),
tree.tag = c(111,112,113,222,223,333,334,335,336,337))
df2 <- data.frame(plot.id = c("plot1", "plot2", "plot3"), load=c(17,
6, 24))
************************************************************************************************
I have gotten close to solving this, but alas I'm on day 2 of
problem-shooting and can't get it! Thanks for any help you might provide.
--Sarah
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-- Sarah Goslee http://www.functionaldiversity.org