Not Equal to
≠

Not Equal to (≠
) is a comparison function which tests whether argument elements are tolerantly unequal. It is the negation of Equal to (=
). Thus it returns 0 if the elements being compared match and 1 if they do not.
Examples
See Equal to for a more detailed treatment of equality testing.
2 2.5 3 3.5 ≠ 2.5
1 0 1 1
Boolean function
When the arguments to Not Equal to are Boolean, it is the exclusive or or xor function:
≠ 
0 
1


0

0 
1

1

1 
0

Xor is one of the most important Boolean functions because it is equivalent to addition of the arguments with modulus 2. Like addition, it is commutative and associative. It is also equivalent to subtraction with modulus 2 because the negative of a number is the same as the original number (mod 2): the negative of an odd number is still odd, and the negative of an even number is still even.
Reduction of a Boolean vector using Not Equal to yields 1 if there were an odd number of 1s in the argument and 0 otherwise. In APL, if v
is a Boolean vector then ≠/v
2+/v
.
External links
Documentation
APL builtins [edit]  

Primitive functions  
Scalar  
Monadic  Conjugate ∙ Negate ∙ Signum ∙ Not ∙ Roll ∙ Type  
Dyadic  Add ∙ Subtract ∙ Times ∙ Divide ∙ Equal to (Xnor) ∙ Not Equal to (Xor) ∙ Minimum ∙ Maximum ∙ Comparison functions ∙ Complex  
NonScalar  
Structural  Shape ∙ Reshape ∙ Tally ∙ Depth ∙ Ravel ∙ Reverse ∙ Raze ∙ Mix ∙ Cut (K) ∙ Pair ∙ Replicate ∙ Partitioned Enclose  
Selection  First ∙ Take ∙ Drop ∙ Unique ∙ Identity ∙ Select ∙ Bracket index  
Selector  Index generator ∙ Interval Index ∙ Indices  
Computational  Match ∙ Not Match ∙ Nub Sieve ∙ Format ∙ Execute  
Primitive operators  Monadic  Each ∙ Replicate ∙ Commute ∙ Function axis  
Dyadic  Beside ∙ Bind ∙ Reverse Compose  
Quad names  
Arrays  Index origin ∙ Migration level  
Functions  
Operators 