[R] calculate difference of consecutive cells in vector
Max Kauer
MaximilianOtto at gmx.at
Wed Mar 22 21:35:34 CET 2006
Hi
in dataframe I want to subtract the "next" value in the list from the former
one to get this:
name var1 output
a 9 506
b 515 512
c 1027 453
so I subtract: table$var1[2]-table$var1[1] and write it into table$output[1]
etc..
I did this with:
for (i in 1:(length(table$var1)){
table$output[i] <- table$var1[i+1]-table$var1[i] }
it works but it get extremely slow for a large table.
I bet there is a better way to do this in R with "sapply" or something
similiar, but I couldn't figure out how.
I'd apprechiate any idea
Thanks!
Max
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