Difference between revisions of "Scilab/C4/File-handling/English-timed"
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Revision as of 16:14, 21 August 2014
| Time | Narration |
| 00:01 | Welcome to this spoken tutorial on File Handling using Scilab. |
| 00:06 | In this tutorial, we will learn |
| 00:08 | File Handling with the following functions; |
| 00:11 | Write Function |
| 00:12 | Read Function |
| 00:14 | mopen |
| 00:15 | mclose |
| 00:16 | For Demonstration i am using Ubuntu Linux12.04 operating system with Scilab version 5.3.3 installed |
| 00:26 | You should have Basic knowledge of Scilab. |
| 00:29 | If not, for relevant spoken tutorials please visit spoken hyphen tutorial dot org |
| 00:36 | Now we will see some functions in scilab which are useful for File Handling. |
| 00:41 | File Handling involves-
|
| 00:44 | writing to a file using write function, |
| 00:47 | reading from a file using read function, |
| 00:51 | opening an existing file using mopen function and |
| 00:55 | closing an already opened file using mclose function. |
| 01:00 | Let us start with writing data to a file. |
| 01:03 | For this purpose the write() command is used.
|
| 01:07 | Switch to the scilab console window. |
| 01:10 | To begin with let us create a matrix of random numbers. |
| 01:15 | Type; random underscore matrix is equal to rand into bracket 20 comma 1 close the bracket semicolon and press enter
|
| 01:29 | Now check the present working directory. |
| 01:32 | Type pwd
|
| 01:34 | In my case the present working directory is slash home slash fossee |
| 01:39 | Make sure that you are in a directory where you have read & write permission , before you execute these commands.
|
| 01:47 | Now we will write the content of variable random underscore matrix into a text file using the write command.
|
| 01:55 | Type;--> write into bracket into quotes random dash numbers dot txt close the quotes comma random underscore matrix close the bracket and press enter
|
| 02:18 | Let us see whether this file has been created. |
| 02:21 | I will minimize the scilab console window.
|
| 02:23 | And open the file which will be created and saved in the fossee directory of my computer. |
| 02:33 | You can see the data from variable random underscore matrix is written in a text file random dash numbers dot txt |
| 02:42 | I will close this file. |
| 02:45 | Coming back to the scilab console. |
| 02:47 | Now we will see how to read the data from a file. |
| 02:50 | For this we will use the command read as follows, |
| 02:55 | Type new underscore vector is equal to read into bracket into quote random dash numbers dot txt close the quotes comma 20 comma 1 close the bracket and press enter. |
| 03:18 | The read command reads all the data from the file mentioned in the argument, |
| 03:23 | In this case random dash numbers dot txt, |
| 03:27 | And stores in the variable new underscore vector |
| 03:31 | Press Enter to continue the display |
| 03:35 | If we modify the above command as
|
| 03:39 | new underscore vector is equal to read into bracket into quote random dash numbers dot txt comma 19 comma 1 |
| 03:49 | The read command reads only 19 data values from the file mentioned in this argument. |
| 03:56 | In this case random dash numbers dot txt
|
| 03:59 | And stores in the variable new underscore vector. |
| 04:03 | Issue this command on the scilab console and verify the output.
|
| 04:08 | Now let us see about the mopen function:
|
| 04:12 | fd = mopen into bracket file-name comma mode |
| 04:17 | mopen command is used to open an existing file in a way compatible to C fopen procedure.
|
| 04:25 | mode is a character string that controls whether the file is opened for
|
| 04:30 | r = Opens the file for reading.
|
| 04:34 | rb = Opens a binary file for reading.
|
| 04:39 | rt = Opens a text file for reading.
|
| 04:43 | w = Creates a new file for writing, or opens and truncates a file to zero length.
|
| 04:50 | wb = Creates a new binary file for writing, or opens and truncates a file to zero length.
|
| 04:58 | wt = Creates a text binary file for writing, or opens and truncates a file to zero length.
|
| 05:06 | a or ab = Appends (opens a file for writing at the end of the file, or creates a file for writing).
|
| 05:14 | r+ or r+b = Opens a file for update (reading and writing)
|
| 05:20 | For eg fd underscore r is equal to mopen('random-numbers,'rt')
|
| 05:30 | the above command opens the 'random-numbers' as a text and read-only mode.
|
| 05:37 | mclose into bracket fd: |
| 05:40 | closes the opened file by using mopen. |
| 05:43 | where fd is the file descriptor of the opened file |
| 05:48 | If fd is omitted mclose closes the last opened file. |
| 05:53 | That's all we have in this tutorial.
|
| 05:55 | We have learnt -
|
| 05:56 | File Handling with the following functions:
|
| 05:59 | Write Function
|
| 06:00 | Read Function
|
| 06:02 | mopen
|
| 06:03 | mclose
|
| 06:05 | Watch the video available at the following link |
| 06:08 | It summarises the Spoken Tutorial project
|
| 06:11 | If you do not have good bandwidth, you can download and watch it |
| 06:14 | The spoken tutorial Team |
| 06:17 | Conducts workshops using spoken tutorials
|
| 06:20 | Gives certificates to those who pass an online test
|
| 06:23 | For more details, please write to conatct@spoken-tutorial.org
|
| 06:30 | Spoken Tutorial Project is a part of the Talk to a Teacher project
|
| 06:34 | It is supported by the National Mission on Eduction through ICT, MHRD, Government of India. |
| 06:41 | More information on this mission is available at http://spoken-tutorial.org/NMEICT-Intro |
| 06:50 | This is Anuradha Amrutkar from IIT Bombay signing off. |
| 06:54 | Thank you for joining. |
