Chapter 4: Programming in Matlab - College of the Redwoods

264 Chapter 4 Programming in Matlab
>> v=[1 3 6]
v =
1 3 6
>> w=[1 2 4]
w =
1 2 4
The output of the command v>w will return a logical vector of the same size as
the vectors v and w. Locations where the specified relation is true receive a 1
and locations where the specified relation is false receive a 0.
>> v>w
ans =
0 1 1
Because the first entry of v is not larger than the first entry of w, the first entry
of the answer receives a zero (false). Because the second and third entries of the
vector v are larger than the second and third entries of the vector w, the second
and third entries of the answer receive a 1 (true). This is what we mean when we
say “Relational operators always operate element-by-element.”
Like the other array operators we’ve seen that act in an element-by-elemnt
manner, the arrays being compared must have the same size.
>> u=[10 10]
u =
10 10
>> u>v
??? Error using ==> gt
Matrix dimensions must agree.
Comparing with a scalar. One exception to the “same size rule” is when
an array is compared to a scalar. In this case, Matlab tests the scalar against
every element of the other operand.