IS Functions in Matlab:
There are many functions which are built into MATLAB which test whether or not something is true; these function names start with the word is. As these functions are often used in if statements. For illustration, the function termed as isletter returns logical 1 when the argument is a letter of the alphabet, and 0 if it is not:
This outcome can also be found by comparing the character's position within the character encoding, for illustration, for lower case letters.