Obtain a Data Frame from a Systat File

read.systat reads a rectangular data file stored by the Systat SAVE command as (legacy) *.sys or more recently *.syd files.

read.systat(file, to.data.frame = TRUE)

Arguments

file

character variable with the name of the file to read

to.data.frame

return a data frame (otherwise a list)

Details

The function only reads those Systat files that are rectangular data files (mtype = 1), and warns when files have non-standard variable name codings. The files tested were produced on MS-DOS and Windows: files for the Mac version of Systat have a completely different format.

The C code was originally written for an add-on module for Systat described in Bivand (1992 paper). Variable names retain the trailing dollar in the list returned when to.data.frame is FALSE, and in that case character variables are returned as is and filled up to 12 characters with blanks on the right. The original function was limited to reading Systat files with up to 256 variables (a Systat limitation); it will now read up to 8192 variables.

If there is a user comment in the header this is returned as attribute "comment". Such comments are always a multiple of 72 characters (with a maximum of 720 chars returned), normally padded with trailing spaces.

Value

A data frame (or list) with one component for each variable in the saved data set.

References

Systat Manual, 1987, 1989

Bivand, R. S. (1992) SYSTAT-compatible software for modelling spatial dependence among observations. Computers and Geosciences 18, 951–963.

Author

Roger Bivand

Examples

summary(iris)
#>   Sepal.Length    Sepal.Width     Petal.Length    Petal.Width   
#>  Min.   :4.300   Min.   :2.000   Min.   :1.000   Min.   :0.100  
#>  1st Qu.:5.100   1st Qu.:2.800   1st Qu.:1.600   1st Qu.:0.300  
#>  Median :5.800   Median :3.000   Median :4.350   Median :1.300  
#>  Mean   :5.843   Mean   :3.057   Mean   :3.758   Mean   :1.199  
#>  3rd Qu.:6.400   3rd Qu.:3.300   3rd Qu.:5.100   3rd Qu.:1.800  
#>  Max.   :7.900   Max.   :4.400   Max.   :6.900   Max.   :2.500  
#>        Species  
#>  setosa    :50  
#>  versicolor:50  
#>  virginica :50  
#>                 
#>                 
#>                 
iris.s <- read.systat(system.file("files/Iris.syd", package="foreign")[1])
str(iris.s)
#> 'data.frame':	150 obs. of  5 variables:
#>  $ SPECIES : num  1 1 1 1 1 1 1 1 1 1 ...
#>  $ SEPALLEN: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
#>  $ SEPALWID: num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
#>  $ PETALLEN: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
#>  $ PETALWID: num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
summary(iris.s)
#>     SPECIES     SEPALLEN        SEPALWID        PETALLEN        PETALWID    
#>  Min.   :1   Min.   :4.300   Min.   :2.000   Min.   :1.000   Min.   :0.100  
#>  1st Qu.:1   1st Qu.:5.100   1st Qu.:2.800   1st Qu.:1.600   1st Qu.:0.300  
#>  Median :2   Median :5.800   Median :3.000   Median :4.350   Median :1.300  
#>  Mean   :2   Mean   :5.843   Mean   :3.057   Mean   :3.758   Mean   :1.199  
#>  3rd Qu.:3   3rd Qu.:6.400   3rd Qu.:3.300   3rd Qu.:5.100   3rd Qu.:1.800  
#>  Max.   :3   Max.   :7.900   Max.   :4.400   Max.   :6.900   Max.   :2.500