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cl:functions:mismatch [2019/06/15 02:00]
cl:functions:mismatch [2019/06/18 10:00] (current)
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 +====== Function MISMATCH ======
 +
 +====Syntax====
 +  * **mismatch** //​sequence-1//​ //​sequence-2//​ ''&​key''​ //​from-end//​ //test// //​test-not//​ //key// //start1// //start2// //end1// //end2// → //​position//​
 +
 +====Arguments and Values====
 +  * //​sequence-1//​ - a //​[[CL:​Glossary:​sequence]]//​.
 +  * //​sequence-2//​ - a //​[[CL:​Glossary:​sequence]]//​.
 +  * //​from-end//​ - a //​[[CL:​Glossary:​generalized boolean]]//​. The default is //​[[CL:​Glossary:​false]]//​.
 +  * //test// - a //​[[CL:​Glossary:​designator]]//​ for a //​[[CL:​Glossary:​function]]//​ of two //​[[CL:​Glossary:​argument|arguments]]//​ that returns a //​[[CL:​Glossary:​generalized boolean]]//​.
 +  * //​test-not//​ - a //​[[CL:​Glossary:​designator]]//​ for a //​[[CL:​Glossary:​function]]//​ of two //​[[CL:​Glossary:​argument|arguments]]//​ that returns a //​[[CL:​Glossary:​generalized boolean]]//​.
 +  * //key// - a //​[[CL:​Glossary:​designator]]//​ for a //​[[CL:​Glossary:​function]]//​ of one argument, or **[[CL:​Constant Variables:​nil]]**.
 +  * //start1//, //end1// - //​[[CL:​Glossary:​bounding index designator|bounding index designators]]//​ of //​sequence-1//​. The defaults for //start1// and //end1// are ''​0''​ and **[[CL:​Constant Variables:​nil]]**,​ respectively.
 +  * //start2//, //end2// - //​[[CL:​Glossary:​bounding index designator|bounding index designators]]//​ of //​sequence-2//​. The defaults for //start2// and //end2// are ''​0''​ and **[[CL:​Constant Variables:​nil]]**,​ respectively.
 +  * //​position//​ - a //​[[CL:​Glossary:​bounding index]]// of //​sequence-2//,​ or **[[CL:​Constant Variables:​nil]]**.
 +
 +====Description====
 +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 //​[[CL:​Glossary:​false]]//​. Otherwise, the result is a non-negative //​[[CL:​Glossary:​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 //​[[CL:​Glossary:​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//​.
 +
 +====Examples====
 +<​blockquote> ​
 +(mismatch "​abcd"​ "​ABCDE"​ :test #'​[[CL:​Functions:​char-equal]]) <r>4 </r>
 +(mismatch '(3 2 1 1 2 3) '(1 2 3) :from-end [[CL:​Constant Variables:​t]]) <r>3 </r>
 +(mismatch '(1 2 3) '(2 3 4) :test-not #'​[[CL:​Functions:​eq]] :key #'​[[CL:​Functions:​oddp]]) <​r>​[[CL:​Constant Variables:​NIL]] </r>
 +(mismatch '(1 2 3 4 5 6) '(3 4 5 6 7) :start1 2 :end2 4) <​r>​[[CL:​Constant Variables:​NIL]] </r>
 +</​blockquote>​
 +
 +====Side Effects====
 +None.
 +
 +====Affected By====
 +None.
 +
 +====Exceptional Situations====
 +None.
 +
 +====See Also====
 +  * {\secref\TraversalRules}
 +
 +====Notes====
 +The **'':​test-not''​** //​[[CL:​Glossary:​argument]]//​ is deprecated.
 +
 +\issue{SUBSEQ-OUT-OF-BOUNDS} \issue{RANGE-OF-START-AND-END-PARAMETERS:​INTEGER-AND-INTEGER-NIL} \issue{MAPPING-DESTRUCTIVE-INTERACTION:​EXPLICITLY-VAGUE} \issue{TEST-NOT-IF-NOT:​FLUSH-ALL}