comparison - comparison, relational operators

Calling Sequence

a==b

a~=b or a<>b

a<b

a<=b

a>b

a>=b

Parameters

• a : any type of variable for a==b , a~=b a<>b equality comparisons and restricted to real floating point and integer array for order related comparisons a<b , a<=b , a>b , a>=b .
• b : any type of variable for a==b , a~=b a< > b equality comparisons and restricted to real floating point and integer arrays for order related comparisons a<b , a<=b , a>b , a>=b .

Description

Two classes of operators have to be distinguished:

The equality and inequality comparisons: a==b , a~=b (or equivalently a<>b ). These operators apply to any type of operands.

The order related comparisons: a<b , a<=b , a>b , a>=b . These operators apply only to real floating point and integer arrays.

The semantics of the comparison operators also depend on the operands types:

With array variables like floating point and integer arrays, logical arrays, string arrays, polynomial and rationnal arrays, handle arrays, lists... the following rules apply:

If a and b evaluates as arrays with same types and identical dimensions, the comparison is performed element by element and the result is an array of booleans of the same.

If a and b evaluates as arrays with same types, but a or b is a 1 by 1 array the scalar is compared with each element of the other array. The result is an array of booleans of the size of the non scalar operand.

In the others cases the result is the boolean %f

If the operand data types are differents but "compatible" like floating points and integers a type conversion is performed before the comparison.

With other type of operands like function , libraries , the result is %t if the objects are identical and %f in the other cases.

Equality comparison between operands of incompatible data types returns %f .

Examples

    
    //element wise comparisons
    (1:5)==3
    (1:5)<=4 
    (1:5)<=[1 4 2 3 0]
    1<[]
    list(1,2,3)~=list(1,3,3)


    //object wise comparisons
    (1:10)==[4,3]
    'foo'==3
    1==[]
    list(1,2,3)==1

    isequal(list(1,2,3),1)
    isequal(1:10,1)

    //comparison with type conversion
    int32(1)==1
    int32(1)<1.5
    int32(1:5)<int8(3)
    p=poly(0,'s','c')
    p==0
    p/poly(1,'s','c')==0

    
  

See Also

less ,   boolean ,   isequal ,