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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 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 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 At iteration percent i comma Result is colon slash n alpha is equal to percentf comma 33 comma 0.535 close the bracket.
04:12 Here 33 will be displayed in place of percent i (%i) and point 535 (0.535) will be displayed in place of percent f (%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 mprintf 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 at 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 path or by its descriptor previously given.
06:37 save(filename) saves all the current variables in a file defined by filename.
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 save space matrix dash a dash b
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 bracket and press Enter.
08:03 This saves the values of variables in a binary file 'matrix dash a dash b dot dat' (matrix-a-b.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 , 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 - 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.
09:46 The spoken tutorial Team:
09:48 Conducts workshops using spoken tutorials.
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09:54 For more details, please write to
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
10:23 This is Anuradha Amrutkar from IIT Bombay, signing off.
10:26 Thank you for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Sandhya.np14