Unequal¶

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description¶

lhs != rhs or Unequal[lhs, rhs]
    is the negation of Equal: True if lhs and rhs can be decided unequal,
    False if they can be decided equal, otherwise unevaluated.

Examples¶

No verified examples yet for this function.

Implementation notes¶

builtin_unequal is the value-level (not structural) negation of Equal. For every argument pair it first checks expr_eq; on failure it tries compare_numeric to decide equality/inequality numerically. If any pair is found equal it returns False immediately. It returns True only when every pair is provably unequal — either decided by compare_numeric or, for non-comparable values, when both sides are distinct raw data (is_raw_data). If some pair is neither equal nor provably unequal (e.g. symbolic), it returns NULL so the call stays unevaluated. Fewer than two arguments returns True.

Attributes: Protected.

Implementation status¶

Stable — documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

References¶

Source: src/comparisons.c
Specification: docs/spec/builtins/comparisons.md

Notes & additional examples¶

Worked examples¶

In[1]:= 2 != 3
Out[1]= True

In[2]:= 2 != 2
Out[2]= False

In[3]:= a != b
Out[3]= a != b

Notes¶

Unequal (!=) is the negation of Equal: True if the arguments are decidably unequal, False if decidably equal, otherwise it stays unevaluated.