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| [[TableOfContents]] | [[http://mitpress.mit.edu/sicp/full-text/book/book.html|Structure and Interpretation of Computer Programs, 2nd Edition]]这本书中的Lisp代码用Python语言重新实现后写在这里，主要目的是供使用Python的人学习函数式编程作参考。 |
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| == The Elements of Programming == === Expressions === 1. {{{ 486 }}}{{{#!python 486 }}} 1. {{{ (+ 137 349) 486 (- 1000 334) 666 (* 5 99) 495 (/ 10 5) 2 (+ 2.7 10) 12.7 }}}{{{#!python 137 + 349 1000 - 334 5 * 99 10 / 5 2.7 + 10 }}} 1. {{{ (+ 21 35 12 7) 75 (* 25 4 12) 1200 }}}{{{#!python 21 + 35 + 12 + 7 25 * 4 * 12 }}}或者{{{ reduce(int.__add__, [21, 35, 12, 7]) reduce(int.__mul__, [25, 4, 12]) }}} 1. {{{ (+ (* 3 5) (- 10 6)) 19 }}}{{{#!python (3 * 5) + (10 - 6) }}} 1. {{{ (+ (* 3 (+ (* 2 4) (+ 3 5))) (+ (- 10 7) 6)) }}}{{{#!python (3 * ((2*4)+(3+5)) ) + ((10-7)+6) }}} === Naming and the Environment === 1. {{{ (define size 2) }}}{{{#!python size = 2 }}} 1. {{{ size 2 (* 5 size) 10 }}}{{{#!python size 5 * size }}} 1. {{{ (define pi 3.14159) (define radius 10) (* pi (* radius radius)) 314.159 (define circumference (* 2 pi radius)) circumference 62.8318 }}}{{{#!python pi = 3.14159 radius = 10 pi * (radius * radius) circumference = 2 * pi * radius circumference }}} === Evaluating Combinations === 1. {{{ (* (+ 2 (* 4 6)) (+ 3 5 7)) }}}{{{#!python (2+(4*6)) * (3+5+7) }}} === Compound Procedures === 1. {{{ (define (square x) (* x x)) }}}{{{#!python square = lambda x: x*x }}} 1. {{{ (square 21) 441 (square (+ 2 5)) 49 (square (square 3)) 81 }}}{{{#!python square(21) square(2+5) square(square(3)) }}} 1. {{{ (define (sum-of-squares x y) (+ (square x) (square y))) (sum-of-squares 3 4) 25 }}}{{{#!python sum_of_squares = lambda x, y: square(x) + square(y) sum_of_squares(3, 4) }}} 1. {{{ (define (f a) (sum-of-squares (+ a 1) (* a 2))) (f 5) 136 }}}{{{#!python f = lambda a:sum_of_squares(a+1, a*2) f(5) }}} === The Substitution Model for Procedure Application === === Conditional Expressions and Predicates === 1. {{{ (define (abs x) (cond ((> x 0) x) ((= x 0) 0) ((< x 0) (- x)))) }}}{{{#!python abs = lambda x: x if x > 0 else ( 0 if x == 0 else (-x if x < 0 else 0)) }}}或者{{{#!python abs = lambda x: x if x > 0 else (0 if x == 0 else -x) }}} 1. {{{ (define (abs x) (cond ((< x 0) (- x)) (else x))) }}} {{{#!python abs = lambda x: -x if x < 0 else x }}} 1. {{{ (define (abs x) (if (< x 0) (- x) x)) }}}{{{ abs = lambda x: -x if x < 0 else x }}} 1. {{{ (and (> x 5) (< x 10)) }}}{{{#!python x > 5 and x < 10 }}} 1. {{{ (define (>= x y) (or (> x y) (= x y))) }}}{{{#!python greater_or_equal = lambda x, y: x>y or x==y }}} 1. {{{ (define (>= x y) (not (< x y))) }}}{{{#!python greater_or_equal = lambda x, y: not x < y }}} === Example: Square Roots by Newton's Method === 1. {{{ (define (sqrt-iter guess x) (if (good-enough? guess x) guess (sqrt-iter (improve guess x) x))) }}}{{{#!python sqrt_iter = lambda guess, x: guess if good_enough(guess, x) else sqrt_iter(improve(guess, x), x) }}} 1. {{{ (define (improve guess x) (average guess (/ x guess))) }}}{{{#!python improve = lambda guess, x: average(guess, x/guess) }}} 1. {{{ (define (average x y) (/ (+ x y) 2)) }}}{{{#!python average = lambda x, y: (x+y)/2.0 }}} 1. {{{ (define (good-enough? guess x) (< (abs (- (square guess) x)) 0.001)) }}}{{{#!python good_enough = lambda guess, x: abs(square(guess)-x)< 0.001 }}} 1. {{{ (define (sqrt x) (sqrt-iter 1.0 x)) }}}{{{#!python sqrt = lambda x:sqrt_iter(1.0, x) }}} 1. {{{ (sqrt 9) 3.00009155413138 (sqrt (+ 100 37)) 11.704699917758145 (sqrt (+ (sqrt 2) (sqrt 3))) 1.7739279023207892 (square (sqrt 1000)) 1000.000369924366 }}} === Procedures as Black-Box Abstractions === == Procedures and the Processes They Generate == 1.2.1 Linear Recursion and Iteration 1.2.2 Tree Recursion 1.2.3 Orders of Growth 1.2.4 Exponentiation 1.2.5 Greatest Common Divisors 1.2.6 Example: Testing for Primality 1.3 Formulating Abstractions with Higher-Order Procedures 1.3.1 Procedures as Arguments 1.3.2 Constructing Procedures Using Lambda 1.3.3 Procedures as General Methods 1.3.4 Procedures as Returned Values |
<<Include(/SICP的Python实现1.1,,titlesonly, editlink)>> <<Include(/SICP的Python实现1.2,,titlesonly, editlink)>> <<Include(/SICP的Python实现1.3,,titlesonly, editlink)>> = Building Abstractions with Data = = Modularity, Objects, and State = = Metalinguistic Abstraction = = Computing with Register Machines = |
Structure and Interpretation of Computer Programs, 2nd Edition这本书中的Lisp代码用Python语言重新实现后写在这里，主要目的是供使用Python的人学习函数式编程作参考。
Building Abstractions with Procedures
Building Abstractions with Data
Modularity, Objects, and State
Metalinguistic Abstraction