(= item1 item2 ...)

Return T if they're the same.

This function tells you whether two (or more) items are equal:

If they are equal, the result is a T (true).
If not, this function returns nil (false).

If the function contains more than two items, this function returns T (true) when each item to the right is equal to the item on its left. The items can be numbers or strings.

Examples

This expression	Returns
(= 8 8)	T
(= 10 10.0 10)	T
(= "x" "y")	nil
(= "door" "door")	T
(= "door" "door" "door")	T
(= 10)	T

NOTES

Don't confuse the = function with the equal function. Here's the difference: The = function compares numbers and strings; the equal function compares lists.
Both = and equal perform comparisons; neither performs the "equals" function you might expect from arithmetic, such as 1 + 2 = 3. In LISP, that service is provided by the setq function.

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(cond (statement1 result1 ...) ...)

(eq statement1 statement2)

(if test statement1 [statement2])

(while text statement …)

LISP Compatibility

Programming Overview of LISP (LISt Processing) Language