[19355] in s-news-athena
[S] Storage space hint
daemon@ATHENA.MIT.EDU (Michael Camilleri)
Wed Sep 29 17:27:29 1999
Message-Id: <0D94E49D52E0D01181840000F8040B9769EFF8@www.branz.org.nz>
From: Michael Camilleri <branzmtc@branz.org.nz>
To: "'s-news@wubios.wustl.edu'" <s-news@wubios.wustl.edu>
Date: Thu, 30 Sep 1999 09:20:34 +1200
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For those that don't know already, you can half the storage space for a
numeric object by specifying single precision. There are at least 3 ways to
do this:
1) For a vector:
storage.mode(x) <- "single"
2) For a matrix or data frame
data <- convert.col.type(target = data, column.spec = 1:ncol(data),
column.type = "single")
This function appears to be undocumented
or for(i in 1:ncol(data)) storage.mode(data[,i]) <- "single"
3)Use the Data|Change Data Type menu (which calls (2))
Well worth doing if you have large data sets and don't need double precision
accuracy. It does not appear to affect any Splus analyses.
use the object.size(x) function to find out how many bytes your object uses.
Cheers!
Michael Camilleri
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