Determines whether two expressions are equal
Supported Platforms: Windows and Mac OS
When comparing two real numbers (or two lists of real numbers, as in points), the two identical numbers can differ slightly if different methods are used to calculate them. You can specify a fuzz amount to compensate for the difference that may result from the different methods of calculation.
If the eq function finds that two lists or atoms are the same, the equal function also finds them to be the same.
Any atoms that the equal function determines to be the same are also found equivalent by eq. However, two lists that equal determines to be the same may be found to be different according to the eq function.
Given the following assignments:
(setq f1 '(a b c)) (setq f2 '(a b c)) (setq f3 f2) (setq a 1.123456) (setq b 1.123457)
(equal f1 f3) T
(equal f3 f2) T
(equal a b) nil
The a and b variables differ by .000001. Compare a to b:, with fuzz argument of .000001:
(equal a b 0.000001) T
The a and b variables differ by an amount equal to the specified fuzz factor, so equal considers the variables equal.