[R] Moving column averaging

[B77S]

# need zoo to use rollapply()

# your data (I called df)
df <- structure(list(a = 1:2, b = 2:3, c = c(5L, 9L), d = c(9L, 6L), 
    e = c(1L, 5L), f = c(4, 7)), .Names = c("a", "b", "c", "d", 
"e", "f"), class = "data.frame", row.names = c(NA, -2L))

# transpose and make a zoo object
df2 <- zoo(t(df))

#rollapply to get means and transpose back
means <- t(rollapply(df2, width=2, by=2, FUN=mean))

# adding the combined column names you requested
colnames(means) <- apply(matrix(names(df), nrow=2), 2, paste, collapse=", ") 


HTH


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