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Artificial Intelligence Week 2 : SEARCH - LISP

Artificial Intelligence Week 2 : SEARCH - LISP. 최 윤 정 참고 http://www.cs.cmu.edu/~dst/LispBook/index.html. 함수와 데이터. int add( int i , int j) { return i+j ; }. int divide( int i , int j) { return i /j ; } // 인자의 순서도 중요. 데이터 : 속성 , information

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Artificial Intelligence Week 2 : SEARCH - LISP

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  1. Artificial Intelligence Week 2 : SEARCH - LISP 최 윤 정 참고 http://www.cs.cmu.edu/~dst/LispBook/index.html

  2. 함수와 데이터 int add(inti, int j) { return i+j ; } int divide(inti, int j) { return i/j ; } //인자의 순서도 중요 • 데이터 : 속성, information • 수(number), 단어(word) , 이들의리스트 • interger, float, ratio(비율), string , list • 함수 : 기능, 역할 • 입력된 데이터로 결과(result)를 만들어 내는 box

  3. 함수와 데이터 • FOUR : symbol 4 : integer • +4 : integer + : symbol 7-11 : symbol • 심볼(symbol) : Lisp의 데이터 타입중 하나 • Sequence of letter , digits and special characters • X, My-name, THREE-IS-3 • Special symbols : • T : logical True, Yes • NIL: logical False, No, Emptiness • 술어(Predicate) : 질문-답변 함수 • 결과가 True면 T, False면 Nil을 return • 기본 build-in 함수들 • NUMBERP, SYMBOLP, EQUAL, ODDP,EVENP ..등

  4. Combination function +, add1, add2

  5. List • Most versatiledata type • ( )로 둘러 쌓인 item들의 묶음 • A : symbol, (A) : list • (a b c), (1 2 3), ( I Love You) • 실제 pointer를사용한 cons cell의 연결구조(NIL을 가리키는 cell이 마지막요소) • (RED GREEN BLUE) • ( (BLUE SKY) (GREEN GRASS) (BROWN EARTH))

  6. Exercise

  7. List 함수 : LENGTH  3 • Length : Top-level의 cons cell 개수 • (A (B C) D) : A , ( B C) , D  3 • (A (B C) (D E F) ) : 3 • ( ) = NIL = empty list : 0 • NIL : symbol 이면서 list

  8. EQUAL • (A (B C) D) 와 (A B (C D))는 다름! • 길이와 내부구조, 순서가 모두 같을 때만 같음.

  9. Exercise

  10. FIRST, SECOND, THIRD, and REST

  11. Return a Pointer

  12. CAR and CDR Combination

  13. Exercise >>(setqx '( (a b) ( c d ) (e f ))) >>(car x) >>(car (car (cdr x))) C >>(cdr(car (cdr x))) (D) ( (A B) (C D) (E F ))

  14. CONS : Create a new cons cell

  15. Cons : Nonlist structure (A B C . D) #1 = (#1# . A) #1 = ( A B C . #1#)

  16. Exercise

  17. LIST : creating a list

  18. Exercise

  19. EVAL notation (* 3 (+ 5 6) ) (Oddp ( + 1 6))

  20. Define Function in EVAL Notation ( defun average ( x y) ( / ( + x y) 2.0) )

  21. Symbols and Lists as Data • Evaluating symbols • pi : 3.14159 , Build-in variable ! • Eggplant : ERROR! , unassigned variable • Quote : ‘ • (equal kim park) : ERROR! Unassigned variable. • (equal ‘kim ‘park) : nil

  22. 3-ways to make lists 1. ( cons ‘a ‘(b c)) : (a b c) 2. ( list ‘a ‘b ‘c) : (a b c) 3.

  23. Exercise

  24. Review Exercise Don’t parenthesize variables in the argument list; don’t quote variables;

  25. LISP on Computer

  26. Read-Eval-Print Loop Listener에서 수정 : ctrl -G

  27. defun : define function But , The most frequently occurring errors in LISP are parenthetical errors. It is thus almost imperative to employ some sort of counting or pairing device to check parentheses every time that a function is changed. — Elaine Gord, ‘‘Notes on the debugging of LISP programs,’’ 1964.

  28. Setf : assign a value to a variable > (setf x ’(a b c)) (A B C) > (setf y (cons ’d (cdr x))) (D B C) > x (A B C) > y (D B C)

  29. HEAD, TAIL, and LONG-LIST are all global variables.

  30. COND : if

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