Scilab/C4/User-Defined-Input-and-Output/English-timed
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Time | Narration |
00:01 | Welcome to the spoken tutorial on File handling using Scilab. |
00:06 | In this tutorial, we will learn: |
00:08 | * Input Function |
00:10 | * Formatting the Output |
00:12 | * save function |
00:14 | *load function . |
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 on Scilab please visit spoken hyphen tutorial dot org. |
00:37 | The input() function is used to take the input from the user. |
00:42 | It provides a prompt in the text string for user input. |
00:47 | It waits for input from the keyboard. |
00:51 | If nothing but a carriage return is entered at the prompt, input() function returns an empty matrix. |
00:59 | The input function can be written in two ways: |
01:03 | First, x= input into brackets message to display |
01:09 | second, x= input into brackets ("message to display", "strings"). |
01:17 | In the second example, the second argument is “string”. |
01:22 | So the output is a character string which is the expression entered using the keyboard. |
01:29 | Switch to the Scilab console window and type, |
01:33 | x is equal to input open bracket inside double quotes Enter your age close the double quotes close the bracket and press Enter. |
01:49 | Type 25 and press Enter. |
01:53 | Now type -->y is equal to input into bracket into double quotes Enter your age close the double quotes comma again inside double quotes write string close the bracket and press Enter. |
02:14 | type 25 and press Enter. |
02:18 | We see that in both the cases the input we entered through keyboard, was a number 25. |
02:25 | Now, let us check the type of variable that x and y are. |
02:30 | Let us clear the console using clc command. |
02:34 | We are doing this to validate the use and importance of the argument “string”, given in the second example. |
02:42 | To check the type of variable, let us type |
02:45 | -->typeof into brackets x and press Enter. |
02:51 | Similarly, typeof(y) and press Enter. |
02:57 | You can see it yourself that the first answer stored in x is of type constant and |
03:04 | second answer stored in y, with the argument “string” included in the command, is of type string. |
03:12 | Let us now see how to format the output that is displayed on the console. |
03:17 | This can be done using the mprintf() function. |
03:22 | mprintf() function converts, formats and writes data on to the Scilab console. |
03:28 | It is an interface for C-coded version of printf function. |
03:34 | Let us see an example for this. Switch to the console. |
03:38 | Type-->mprintf into bracket into quotes type iteration percent i comma result is colon slash n alpha equal to percentf comma 33 comma 0.535 close the bracket. |
04:12 | Here 33 will be displayed in place of percent i and point 535 (0.535) will be displayed in place of percent f as a flow, press Enter. |
04:26 | This will give the output as At iteration 33, Result is alpha is equal to 0.535000. |
04:39 | Clear the console. Now let us see another example. |
04:44 | In print f open bracket into quotes value of x is equal to percentage d is taken as a constant comma while value of y is equal to percent s is taken as a string close the quotes comma x comma y close the bracket |
05:19 | In the above example percentage d (%d) is used to insert a constant data stored in variable x and |
05:28 | percentage s (%s) is used to insert a string data stored in variable y. press Enter, you see the output. |
05:38 | Now, let us discuss the use of save and load commands. |
05:43 | To quit Scilab midway through a calculation and to |
05:47 | continue to a later stage, type save thissession. |
05:52 | This will save the current values of all variables to a file called thissession. |
05:58 | This file cannot be edited. |
06:01 | It is in binary format. |
06:04 | When you next start Scilab, type load thissession |
06:08 | and the computation can be resumed where you left off. |
06:13 | The purpose of save and load functions are |
06:16 | The save() command saves all the Scilab current variables in a binary file. |
06:22 | If the variable is a graphic handle, the save function saves all the corresponding graphics_entities definition. |
06:31 | The file can be given either by its paths or by its descriptor previously given. |
06:37 | save(filename) saves all the current variables in a file defined by file name. |
06:45 | save into bracket fd saves all the current variables in the file defined by the descriptor fd. |
06:53 | save(filename,x,y) or save(fd,x,y) saves only named variables x and y. |
07:02 | Let us see an example to illustrate the save and load commands usage. |
07:07 | Switch back to the console. Let us define two matrices, say a and b. |
07:14 | -->a = eye of (2,2) and press Enter. |
07:22 | Type b=ones(a) and press Enter. |
07:28 | Clear the console using clc command. Now type |
07:34 | |
07:42 | or it can also be written as: |
07:46 | save into brackets into quotes matrix dash a dash b dot dat close the quotes comma a comma b close the braket and press Enter. |
08:03 | This saves the values of variables in a binary file matrix dash a dash b dot dat in the present working directory. |
08:12 | You can browse the present working directory to check the existence of this binary file. |
08:17 | You can see it here. I will close the file browser. |
08:22 | Now let us load the file back in to the variables. |
08:26 | Before this, let us clear the variables a and b . |
08:29 | Type clear a space b press Enter. |
08:34 | Let us cross check if these variables are really cleared. |
08:39 | ->a |
08:40 | b |
08:41 | Now let us load back the values from the binary files in these variables a and b using the load command. |
08:49 | Type Load into bracket into quote matrix dash a dash b dot dat close the quotes comma into quotes a comma into quotes b close the bracket and press Enter. |
09:08 | Let us check the values in variables a and b. Clear the console. |
09:14 | Type >a And-->b |
09:18 | You can see the values are loaded back in the variables. |
09:23 | In this tutorial we learnt - |
09:24 | * Input function using input command |
09:28 | * Formatting the output using mprintf command |
09:31 | * save function |
09:33 | * load function |
09:35 | Watch the video available at the link shown below. |
09:38 | It summarizes the Spoken Tutorial project. |
09:41 | If you do not have good bandwidth, you can download and watch it. |
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10:01 | Spoken Tutorial Project is a part of the Talk to a Teacher project. |
10:05 | It is supported by the National Mission on Eduction through ICT, MHRD, Government of India. |
10:12 | More information on this mission is available at http://spoken-tutorial.org/NMEICT-Intro. |
10:23 | This is Anuradha Amrutkar from IIT Bombay, signing off. |
10:26 | Thank you for joining. |