mismatch sequence-1 sequence-2
{&key from-end test test-not key start1 start2 end1 end2}
=> position
Sequence-1---a sequence.
Sequence-2---a sequence.
from-end---a generalized boolean. The default is false.
test---a designator for a function of two arguments that returns a generalized boolean.
test-not---a designator for a function of two arguments that returns a generalized boolean.
start1, end1---bounding index designators of sequence-1. The defaults for start1 and end1 are 0 and nil, respectively.
start2, end2---bounding index designators of sequence-2. The defaults for start2 and end2 are 0 and nil, respectively.
key---a designator for a function of one argument, or nil.
position---a bounding index of sequence-1, or nil.
The specified subsequences of sequence-1 and sequence-2 are compared element-wise.
The key argument is used for both the sequence-1 and the sequence-2.
If sequence-1 and sequence-2 are of equal length and match in every element, the result is false. Otherwise, the result is a non-negative integer, the index within sequence-1 of the leftmost or rightmost position, depending on from-end, at which the two subsequences fail to match. If one subsequence is shorter than and a matching prefix of the other, the result is the index relative to sequence-1 beyond the last position tested.
If from-end is true, then one plus the index of the rightmost position in which the sequences differ is returned. In effect, the subsequences are aligned at their right-hand ends; then, the last elements are compared, the penultimate elements, and so on. The index returned is an index relative to sequence-1.
(mismatch "abcd" "ABCDE" :test #'char-equal) => 4 (mismatch '(3 2 1 1 2 3) '(1 2 3) :from-end t) => 3 (mismatch '(1 2 3) '(2 3 4) :test-not #'eq :key #'oddp) => NIL (mismatch '(1 2 3 4 5 6) '(3 4 5 6 7) :start1 2 :end2 4) => NIL
section Traversal Rules and Side Effects
The :test-not argument is deprecated.
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