3>2>1 returns logical 0?

When I run 3>2>1 it returns logical 0 (false). Sorry if its a basic question but I can't understand how this is not true.

Answer 1

[Stephen23]

The basic problem is that you are attempting two logical relations simultaneously: MATLAB's relational operators are binary operators, so they only support one comparison at once. In summary:

X<A<Y     % is NOT valid for comparing A against X and Y
X<A & A<Y % This compares A with both X and Y

In MATLAB logical relational operators follow the standard rules of operator precedence. Look at this example carefully:

>> 3<4<2
ans =
     1

The output is true, so does this mean that 4<2 ? Of course not, we just have to remember the operator precedence rules, just like in high school. This is evaluated according to those rules as:

>> (3<4)<2
ans =
     1

where

>> 3<4
ans =
     1

So 3<4<2 is actually equivalent to 1<2, which is of course very true:

>> 1<2
ans =
      1

Answer 2

[Guillaume]

You cannot chain comparisons. You have to use logical operators.

3>2>1

is the same as

(3>2) > 1

which evaluates to

true > 1

which is false since true is the same as 1.

To do what you want:

3>2 && 2>1

Answer 3

[William]

I think the compiler probably solves this:

(3>2)>1
 ans = 
        0

i.e 1>1= 0