Difference between revisions of "Scilab/C4/File-handling/English"

• File Handling with the following functions;
  • Write Function
  • Read Function
  • mopen
  • mclose

For Demonstration i am using Ubuntu Linux12.04 operating system with Scilab version 5.3.3 installed

You should have

1. Basic knowledge of Scilab.
2. If not, for relevant spoken tutorials please visit spoken hyphen tutorial dot org

File Handling involves-

• writing to a file using write function,
• reading from a file using read function,
• open an existing file using mopen function and
• closing an already opened file using mclose function.

For this purpose the write() command is used.

--> random_matrix = rand(20,1)

random_matrix =

0.2113249

0.7560439

0.0002211

0.3303271

0.6653811

0.6283918

0.8497452

0.6857310

0.8782165

0.0683740

0.5608486

0.6623569

0.7263507

0.1985144

0.5442573

0.2320748

0.2312237

0.2164633

0.8833888

0.6525135

-->random underscore matrix is equal to rand in the bracket 20 comma 1 close the bracket semicolon and press enter

--> pwd

-->pwd

ans =

/home/fossee

In my case the present working directory is slash home slash fossee

Make sure that you are in a directory where you have read & write permission , before you execute these commands.

Type;--> write into bracket into quotes random dash numbers dot txt close  the  quotes comma random underscore matrix close the bracket and press enter

I will minimize the scilab console window.

And open the file which will be created and saved in the fossee directory of my computer.

-->new_vector = read('random-numbers.txt', 20, 1)

new_vector =

0.2113249

0.7560439

0.0002211

0.3303271

0.6653811

0.6283918

0.8497452

0.6857310

0.8782165

0.0683740

0.5608486

0.6623569

0.7263507

0.1985144

0.5442573

0.2320748

0.2312237

0.2164633

0.8833888

0.6525135

For this we will use the command read as follows,

Typenew underscore vector is equal to read into bracket in to quote random dash numbers Dot txt close the quote comma 20 comma 1 close the bracket and press enter.

The read command reads all the data from the file mentioned in the argument,

In this case random dash numbers dot txt,

And stores in the variable new underscore vector Press Enter to continue the display

-->new_vector = read('random-numbers.txt', 19, 1)

new underscore vector is equal to read into bracket into quote random dash numbers Dot txt comma 19 comma 1

The read command reads only 19 data values from the file mentioned in this argument.

In this case random dash numbers dot txt

And stores in the variable new underscore vector.

Issue this command on the scilab console and verify the output.

fd = mopen(file-name, mode)

mopen command is used to open an existing file in a way compatible to C fopen procedure.

mode is a character string that controls whether the file is opened for

r = Opens the file for reading.

rb = Opens a binary file for reading.

rt = Opens a text file for reading.

w = Creates a new file for writing, or opens and truncates a file to zero length.

wb = Creates a new binary file for writing, or opens and truncates a file to zero length.

wt = Creates a text binary file for writing, or opens and truncates a file to zero length.

a or ab = Appends (opens a file for writing at the end of the file, or creates a file for writing).

r+ or r+b = Opens a file for update (reading and writing)

-->fd_r = mopen('random-numbers.txt','rt')
 fd_r  =

    1. 

fd underscore r is equal to mopen('random-numbers,'rt')

the above command opens the 'random-numbers' as a text and read-only mode.

mclose command closes the opened file by using mopen.

mclose(fd)

where fd is the file descriptor of the opened file

If fd is omitted mclose closes the last opened file.

-->mclose(fd_r)

ans =

0.

Where fd is the file descriptor of the opened file.

If fd is omitted mclose closes the last opened file.

Thats all we have in this tutorial.

You have learnt - 

• File Handling with the following functions:

Write Function

Read Function

mopen

mclose

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