read

Name

read — matrices read

Calling Sequence

[x]=read(file-desc,m,n,[format])
[x]=read(file-desc,m,n,k,format)

Parameters

file-desc: character string specifying the file name or integer value specifying logical unit (see file).
m, n: integers (dimensions of the matrix x). Set m=-1 if you do not know the numbers of rows, so the whole file is read.
format : character string, specifies a "Fortran" format. This: character string must begin with a right parenthesis and end with a left parenthesis. Formats cannot mix floating point or character edition modes.
k: integer or vector of integer

Description

reads row after row the mxn matrix x (n=1 for character chain) in the file file-desc (string or integer). Each row of the matrix x begin in a new line of file-desc file. Depending on format, a given row of the x matrix may be read from more than one line of file-desc file.

The type of the result will depend on the specified format. If format contains only (d,e,f,g) descriptors the function tries to read numerical data (the result is matrix of real numbers).

If format contains only a descriptors the function tries to read character strings (the result is a character string column vector). In this case n must be equal to 1. Warning: The character strings are truncated when they are longuer than 4093.

Examples for format:

 
(1x,e10.3,5x,3(f3.0))
(10x,a20)

When format is omitted datas are read using numerical free format: blank, comma and slash may be used as data separators, n*v may be use to represent n occurrences of value n.

A direct access file can be used if using the parameter k which is is the vector of record numbers to be read (one record per row), thus m must be m=prod(size(k)).

To read on the keyboard use read(%io(1),...).

Remark

Last line of data files must be terminated by a newline to be taken into account.

Examples

 
if MSDOS then unix('del foo');
else unix('rm -f foo'); end
A=rand(3,5); write('foo',A);
B=read('foo',3,5)
B=read('foo',-1,5)
read(%io(1),1,1,'(a)')  // waits for user's input