datacreate#

Purpose#

Creates a real dataset.

Format#

fh = datacreate(filename, vnames, col, dtyp, vtyp)#

Parameters:

filename (string) – name of data file.
vnames (string or Nx1 string array) – names of variables.
col (scalar) – number of variables.
dtyp (scalar) –
data precision, one of the following:

2

2-byte, signed integer.

4

4-byte, single precision.

8

8-byte, double precision.
vtyp (scalar or Nx1 vector) –
types of variables, may contain one or both of the following:

0

character variable.

1

numeric variable.

Returns:

fh (scalar) – file handle.

Examples#

// Name variables
string vnames = "V";

/*
** Create file handle
** with vnames and 100 variables
** containing double precision
** numeric data.
*/
fh = datacreate("myfile.dat", vnames, 100, 8, 1);

// Generate random complex data
x = rndn(500,100);

// Write file using file handle
r = writer(fh, x);
ret = close(fh);

This example creates a double precision data file called myfile.dat, which is placed in the current directory. The file contains 100 columns with 500 observations (rows), and the columns are given the names 'V001', 'V002', ..., 'V100'.

Remarks#

The file handle returned by datacreate() is a scalar containing a positive integer value that uniquely identifies each file. This value is assigned by GAUSS when the create, datacreate(), datacreatecomplex(), open or dataopen() commands are executed. The file handle is used to reference the file in the commands readr() and writer(). If datacreate() fails, it returns a -1. If filename does not include a path, then the file is placed in the current directory. The file is given a .dat extension if no extension is specified.

If col is set to 0, then the number of columns in the dataset is controlled by the contents of vnames. If col is positive, then the file will contain col columns.

If vnames contains col elements, then each column is given the name contained in the corresponding row of vnames. If col is positive and vnames is a string, then the columns are given the names vnames1, vnames2, ..., vnamesN (or vnames01, vnames02, ..., vnamesN), where \(N = col\). The numbers appended to vnames are padded on the left with zeros to the same length as \(N\).

The dtyp argument allows you to specify the precision to use when storing your data. Keep in mind the following range restrictions when selecting a value for dtyp:

Data Type	Digits	Range
integer	5	\(-32768 \lt X \lt 32767\)
single	6-7	\(8.43\times10^{-37} \lt\|X\| \leq 3.37 \times 10^{+38}\)
double	15-16	\(4.19\times10^{-307} \lt \|X\| \lt 1.67\times10^{+308}\)

Source#

datafile.src

2	2-byte, signed integer.
4	4-byte, single precision.
8	8-byte, double precision.

0	character variable.
1	numeric variable.