Re: [R] Reading sas7bdat files directly
The dsread output is little-endian, as that's the native format for
floats on the Wintel platform. The byte order should stay the same if
converting directly to a float, using a data structure like (C/C++):
union {
char bytes[8];
double value;
}
If reading the values with a SAS HEX informat, the bytes will need to be
reversed. It's obviously trivial for me to add an endian-ness option,
I'll do that later
Chris.
On 02/03/2010 02:06, Roger DeAngelis(xlr82sas) wrote:
Hi,
It looks like we may need to swap bytes(little endian to big endian). I
will look into it tonight.
As a side note, SAS reserves 28 floats for missing values. It should be
easy to convert these to NaN on input to R.
You can test this in SAS by converting the 16 char floats to ieee8. in SAS
and doing a put. The result will be A, B...Z, . and _.
SAS code that produced the listing is below.
Here are the floats that map to the 28 missing values in SAS
A FD00
B FC00
C FB00
D FA00
E F900
F F800
G F700
H F600
I F500
J F400
K F300
L F200
M F100
N F000
O EF00
P EE00
Q ED00
R EC00
S EB00
T EA00
U E900
V E800
W E700
X E600
Y E500
Z E400
_ FF00
. FE00
data mis;
retain A .A B .B C .C D .D E .E F .F G .G H .H I .I J .J K .K L .L M .M
N .N O .O P .P Q .Q R .R S .S T .T U .U V .V W .W X .X Y .Y Z .Z
_ ._ DOT .;
array mis[28] A B C D E F G H I J K L M N O P Q R S T U V W X Y Z _ DOT;
do idx=1 to 28;
hex=put(mis[idx],ieee8.);
xeh=put(hex,hex16.);
put @1 mis[idx] @6 xeh;
end;
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Reading sas7bdat files directly
dsread (http://www.oview.co.uk/dsread) was updated yesterday, to include various new features as suggested here and elsewhere. Of particular interest might be: - you can now use the /c and /v options together to get dataset contents in CSV format for easier importing; - there is now a /l option for lossless representation of numerics in the output. Numerics will appear as (eg) '0xf03f' giving the exact hex value of each of the eight bytes making up the IEEE float value. Please continue to report bugs or feature requests here or on the above web page. Thanks, Chris. -- View this message in context: http://n4.nabble.com/Reading-sas7bdat-files-directly-tp1469515p1574340.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Reading sas7bdat files directly
I suppose a link would have added usefulness: http://www.oview.co.uk/dsread Chris. -- View this message in context: http://n4.nabble.com/Reading-sas7bdat-files-directly-tp1469515p1567256.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Reading sas7bdat files directly
No problem, Frank, I'm glad that you think it will be useful. I will be making changes to dsread in the coming weeks so you may want to hold off with your helper function in case my changes break it (the formatting of the variable metadata listing may well change). Re: the metadata, feel free to suggest an alternate output format that would make this a cleaner process. For example, I have in mind to allow the -c (contents) and -v (CSV) flags together, in which case the dataset metadata will be output in CSV format. Any other suggestions or comments are welcomed. Chris. -- View this message in context: http://n4.nabble.com/Reading-sas7bdat-files-directly-tp1469515p1567504.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] Replacing NA values when building matrix using tapply
Hi,
I'm building a matrix m from a data frame d which includes the matrix row,
column and value.
This works well enough:
m - tapply(d[,value],d[,c(row,column)],c)
However, I'd like to replace any missing values with 0, not NA. The
obvious doesn't work, however:
m - tapply(d[,value],d[,c(row,column)],function(x)
{ifelse(is.na(x),0.0,x)})
I can always do this:
m - tapply(d[,value],d[,c(row,column)],c)
m[is.na(m)] - 0.0
But it's wasteful to process the table again. Any ideas?
--
Christopher D. Long, San Diego Padres, 100 Park Boulevard, San Diego CA
Score: 0, Diff: 1, clong killed by a Harvard Math Team on 1
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
