Representing logical true and false, MATLAB in Statistics

Representing Logical true and False:

It has been stated that expressions which are theoretically true really have the integer value of 1, and expressions which are theoretically false really have the integer value of 0.Exhibiting the concepts of logical true and false in the MATLAB is somewhat different: the concept of false is presented by the integer value of 0, but the concept of true can be presented by any non-zero value (not merely the integer 1). This can lead to a few strange Boolean expressions. For illustration, consider the following if statement:

>> if 5

disp('Yes, this is true!')

end

Yes, this is true!

As 5 is a nonzero value, it is a way of telling true. And hence, when this Boolean expression is computed, it will be true, therefore the disp function will be executed and "Yes, this is true" is exhibited. Obviously, this is a pretty bizarre if the statement, one that hopefully would not ever be encountered!

Though, a simple mistake in an expression can lead to this type of answer. For illustration, let's state that the user is prompted for the choice of Y or N for a yes/no question:

letter = input('Choice (Y/N): ','s');

In the script we might want to execute a specific action if the user responded with 'Y'. Nearly all scripts would permit the user to enter either lower- or uppercase (example, either 'y' or 'Y') to specify yes. The appropriate expression that would return true if the value of letter was 'y' or 'Y' would be

letter == 'y' || letter == 'Y'

Though, if by fault this was written as:

letter == 'y' || 'Y'

this expression would  forever be true, regardless of the value of the variable letter. This is as 'Y' is a nonzero value; therefore it is a true expression. The first section of the expression might be false, but as the second expression is true the whole expression would be true.

Posted Date: 10/19/2012 3:17:47 AM | Location : United States







Related Discussions:- Representing logical true and false, Assignment Help, Ask Question on Representing logical true and false, Get Answer, Expert's Help, Representing logical true and false Discussions

Write discussion on Representing logical true and false
Your posts are moderated
Related Questions
Example of Core objects: The one core graphics object is a line that is also what the plot function produces. Here is an illustration of generating a line object, altering som

fscanf function - file function: The fscanf reads matrix variable mat columnwise from the file specified by fid. The 'format' involves conversion characters much similar to th

Execution of persistent variables: The functions can also be called from the script or from the Command Window, as shown here. For illustration, the functions are called first

Illustration of Mode When there is more than one value with similar (highest) frequency, then the smaller value is mode. In the case below, as 3 and 8 appear twice in the vecto

Rectangle - graphics objects: The other core graphics object is the rectangle that can have curvature added to it (!!). Merely calling the function rectangle without any argum

Generic code for Reading from Files: The generic code to complete this is as shown below:   fid = fopen('filename'); if fid == -1    disp('File open not suc

Polynomials: Simple curves are polynomials of various degrees, or orders. The degree is the integer of the highest exponent in the expression. The illustrations are as follows

Function polyval - interpolation: The function polyval can then be used to compute the polynomial at particular values. For illustration, we could compute at every value in th

Representing Logical true and False: It has been stated that expressions which are theoretically true really have the integer value of 1, and expressions which are theoretical

Illustrations of Sequential search: The two illustrations of calling such function is as shown below: >> values = [85 70 100 95 80 91]; >> key = 95; >> seqsearch