Opening and closing a file, MATLAB in Statistics

Opening and Closing a File:

The Files are opened with the fopen function. By the default, fopen function opens a file for reading. If the other mode is preferred, a permission string is used to identify which mode (example, writing or appending). The fopen function returns 1 when it is not successful in opening a file, or an integer value, that becomes the file identifier when it is successful. The file identifier is then used to refer the file whenever calling other file I/O functions. The common form is as shown below:

fid = fopen('filename', 'permission string');

The permission strings include:

r reading (this is the default)

w writing

a appending

View helps fopen for others.

 

Afterward the fopen is tried; the value returned must be tested to make sure that the file was efficiently opened. For illustration, if the files do not exist, the fopen will not be successful. As the fopen function returns -1 when the file was not found, this can be checked to decide whether to print an error message or to continue and use the file. For illustration, if it is preferred to read from a file 'samp.

dat':

fid = fopen('samp.dat');

if fid == -1

   disp('File open not successful')

else

   % Carry on and use the file!

end

 

The Files must be closed whenever the program has finished the reading from or writing to them. The function which accomplishes this is the fclose function, that returns 0 if the file close was successful, or -1 if not. The Individual files can be closed by identifying the file identifier, or if more than one file is open, then all the open files can be closed by passing the string 'all' to the fclose function. The common forms are as shown below:

closeresult = fclose(fid);

closeresult = fclose('all');

 

This must also be checked with an if-else statement to make sure that it was successful.

Posted Date: 10/20/2012 6:18:08 AM | Location : United States







Related Discussions:- Opening and closing a file, Assignment Help, Ask Question on Opening and closing a file, Get Answer, Expert's Help, Opening and closing a file Discussions

Write discussion on Opening and closing a file
Your posts are moderated
Related Questions
Polynomials: Simple curves are polynomials of various degrees, or orders. The degree is the integer of the highest exponent in the expression. The illustrations are as follows

Vectors of nested structures: The Combining vectors and nested structures are possible to have a vector of structures in which several fields are structures themselves. Here i

Vectorizing: In most of the cases in MATLAB, loops are not essential. As MATLAB is written specifically to work with the vectors and matrices, most operations can be completed

Illustration of tracing a error: The one way of following the flow of function, or tracing it, is to use the echo function. The echo function, that is a toggle, will show each

Illustrations of Sequential search: The two illustrations of calling such function is as shown below: >> values = [85 70 100 95 80 91]; >> key = 95; >> seqsearch

Use of function polyval: The better the curve fit, the more exact these interpolated and extrapolated values will be. By using the subplot function, we can loop to display the

Sequential Search: A sequential search is completed by looping through the vector element-by-element starting from the beginning, looking for the key. Usually the index of the

Graphics objects: The objects involve graphics primitives like lines and text, and also the axes used to orient the objects. These objects are organized hierarchically, and the

Function polyval - interpolation: The function polyval can then be used to compute the polynomial at particular values. For illustration, we could compute at every value in th

Illustration of Mode When there is more than one value with similar (highest) frequency, then the smaller value is mode. In the case below, as 3 and 8 appear twice in the vecto