[R] simple averaging question?

[Chuck Cleland]

Jeff Miller wrote:
> Hi all,

> Suppose I have a column vector of 600 measurements taken in 1s intervals.
> 
> What I want is a new vector with the averages for each min (so there would
> be 10 entries).
> 
> Is there an efficient way to do this? I’ve been doing it with a ‘for’ loop
> but something tells me there is a simple command that is more efficient.

  How about something like this?

y <- runif(600)

df <- data.frame(minute = rep(1:10, each=60), y = y)

with(df, tapply(y, minute, mean))
        1         2         3         4         5
0.4664301 0.4622071 0.5159511 0.4744836 0.5282750
        6         7         8         9        10
0.4670941 0.5091410 0.4648349 0.5227221 0.5251926

> Jeff
> 
>  
> 
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Chuck Cleland, Ph.D.
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