Difference between revisions of "Scilab/C4/File-handling/English-timed"
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Revision as of 09:26, 5 March 2015
| 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 Linux 12.04 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 quotes 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 summarizes 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. |
