Hi there,
This is summary and patch for a bug in read.dbf, demonstrating in
Message-Id: <[EMAIL PROTECTED]>.
After consulting Rjpwiki, a cyber-community of R user in Japan, the
cause was found, and the patch of solution was proposed.
Overflowing occurs when we use read.dbf for reading a dbf file having
a field of longer signed integer. For example,
$ dbf2txt test.dbf
#KEYCODE
422010010
42201002101
42201002102
42201002103
42201002104
422010060
422010071
422010072
42201008001
42201008002
The KEYCODE field is numeric type, 19 digits, and no decimal. You can
create this file with OpenOffice.org Calc, txt2dbf, and so on. You
also prepare a file of CSV format.
> library(foreign)
> cbind(read.csv("test.csv"),read.dbf("test.dbf"))
KEYCODE KEYCODE
1 422010010 422010010
2 42201002101 NA
3 42201002102 NA
4 42201002103 NA
5 42201002104 NA
6 422010060 422010060
7 422010071 422010071
8 422010072 422010072
9 42201008001 NA
10 42201008002 NA
This is not reproducible when the field has decimals like numeric
type, 19 digits, and 5 decimals.
The patch written of Mr. Eiji Nakama is followed.
--- foreign.orig/src/dbfopen.c 2005-08-19 18:54:06.000000000 +0900
+++ foreign/src/dbfopen.c 2005-08-19 18:58:06.000000000 +0900
@@ -970,7 +970,8 @@
|| psDBF->pachFieldType[iField] == 'F' )
/* || psDBF->pachFieldType[iField] == 'D' ) D is Date */
{
- if( psDBF->panFieldDecimals[iField] > 0 )
+ if( psDBF->panFieldDecimals[iField] > 0 ||
+ psDBF->panFieldSize[iField] > 9 )
return( FTDouble );
else
return( FTInteger );
After adopting the patch, read.dbf works correctly.
> cbind(read.csv("test.csv"),read.dbf("test.dbf"))
KEYCODE KEYCODE
1 422010010 422010010
2 42201002101 42201002101
3 42201002102 42201002102
4 42201002103 42201002103
5 42201002104 42201002104
6 422010060 422010060
7 422010071 422010071
8 422010072 422010072
9 42201008001 42201008001
10 42201008002 42201008002
--
Susumu Tanimura
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