Determines whether two expressions are identical
Supported Platforms: Windows, Mac OS, and Web
Signature
(eq expr1 expr2)
- expr1
-
Type: Integer, Real, String, List, Ename (entity name), T, or nil
The expression to be compared.
- expr2
-
Type: Integer, Real, String, List, Ename (entity name), T, or nil
The expression to compare with expr1.
Return Values
Type: T or nil
T if the two expressions are identical; otherwise nil.
Remarks
The eq function determines whether expr1 and expr2 are bound to the same object (by setq, for example).
Examples
Given the following assignments:
(setq f1 '(a b c)) (setq f2 '(a b c)) (setq f3 f2)
Compare f1 and f3:
(eq f1 f3) nil
eq returns nil because f1 and f3, while containing the same value, do not refer to the same list.
Compare f3 and f2:
(eq f3 f2) T
eq returns T because f3 and f2 refer to the same list.