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

• File Handling
  • Write Function
  • Read Function
  • mopen Function
  • mclose Function

You should have

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

For Demonstration: Ubuntu Linux12.04 operating system is used with Scilab version 5.3.3 installed

File Handling involves-

• writing to a file,
• reading from a file,
• open an existing file and
• closing the opened file

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 inside bracket 20 comma 1

--> 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.

--> write inside bracket open single quotes random dash numbers dot txt close single quotes comma random underscore matrix

I will minimize the scilab console window.

And open the file which will be created and saved in the home 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,

new underscore vector is equal to read open bracket open single quote random dash numbers Dot txt close single quote comma 20 comma 1 close bracket

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

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

new underscore vector is equal to read open bracket open single quote randomdash numbers Dot txt close single quotecomma 19 comma 1 close bracket

The read command reads only 19 data values from the file mentioned in the 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.txt','rt')

the above command opens the 'random-numbers' as 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.

the above command closes the 'random-numbers.txt' file.

Let us summarize what we learnt -

• File Handling with the following functions:

Write Function

Read Function

mopen Function

mclose Function

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