Re: [R] Incrementally building histograms

From: Rolf Turner <r.turner_at_auckland.ac.nz>
Date: Thu, 06 Nov 2008 15:10:51 +1300

On 6/11/2008, at 2:01 PM, Andre Nathan wrote:

> Hello
>
> I need to build a histogram from data (numbers in the [0,1] interval)
> stored in a number of different files. The total amount of data is
> very
> large, so I can't load everything to memory and then simply call
> hist().
> Since what I actually need are the histogram counts, I'm currently
> doing
> it like this:
>
> breaks <- seq(0, 1, by = 0.01)
> files <- list.files(pattern = "some pattern")
> counts <- 0
> for (file in files) {
> data <- scan(file, quiet = T)
> h <- hist(data, plot = F, breaks = breaks)
> counts <- counts + h$counts
> }
> # and then work with `counts' here
>
> Is there a more efficient and/or idiomatic way to do this?

        No.

                cheers,

                        Rolf Turner

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