2025年python编程 cs61A笔记01-02

科技前沿 • 2025-04-06 12:22 • 阅读 39

大家好，我是讯享网，很高兴认识大家。

What is Computer Science?

什么问题用计算可以解决？
如何用技术高效解决那些问题？
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讯享网
python有很多写法，代码示例：

 content = "ada asdfsf sdfasdfs asdfasdfawsf wwwsadfwww abwwwba" test = content.split() words = set(test) var = { 
   w for w in words if w == w[::-1] and len(w) > 5} print(var) 输出： { 
   'abwwwba'}

讯享网

上面的表达式等同于：

讯享网 for w in words: if w == w[::-1] and len(w) > 5: print({ 
   w})

print输出

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print函数是Non-Pure函数，具有显示的副作用，返回是None，例题：

def with_if_statement(): """ >>> with_if_statement() 1 """ if c(): return t() else: return f() def with_if_function(): return if_function(c(), t(), f()) def c(): "* YOUR CODE HERE *" return True def t(): "* YOUR CODE HERE *" return 1 def f(): "* YOUR CODE HERE *" return print(2)

习题及答案：

讯享网from operator import add, sub def a_plus_abs_b(a, b): """Return a+abs(b), but without calling abs. >>> a_plus_abs_b(2, 3) 5 >>> a_plus_abs_b(2, -3) 5 """ if b < 0: return a - b else: return a + b def two_of_three(a, b, c): """Return x*x + y*y, where x and y are the two largest members of the positive numbers a, b, and c. >>> two_of_three(1, 2, 3) 13 >>> two_of_three(5, 3, 1) 34 >>> two_of_three(10, 2, 8) 164 >>> two_of_three(5, 5, 5) 50 """ return max(a*a+b*b, a*a+c*c, b*b+c*c) def largest_factor(n): """Return the largest factor of n that is smaller than n. >>> largest_factor(15) # factors are 1, 3, 5 5 >>> largest_factor(80) # factors are 1, 2, 4, 5, 8, 10, 16, 20, 40 40 >>> largest_factor(13) # factor is 1 since 13 is prime 1 """ i = 2 while i <= n: if n % i == 0: return int(n/i) else: i+=1 def if_function(condition, true_result, false_result): """Return true_result if condition is a true value, and false_result otherwise. >>> if_function(True, 2, 3) 2 >>> if_function(False, 2, 3) 3 >>> if_function(3==2, 3+2, 3-2) 1 >>> if_function(3>2, 3+2, 3-2) 5 """ if condition: return true_result else: return false_result def with_if_statement(): """ >>> with_if_statement() 1 """ if c(): return t() else: return f() def with_if_function(): return if_function(c(), t(), f()) def c(): "* YOUR CODE HERE *" return True def t(): "* YOUR CODE HERE *" return 1 def f(): "* YOUR CODE HERE *" return print(2) def hailstone(n): """Print the hailstone sequence starting at n and return its length. >>> a = hailstone(10) 10 5 16 8 4 2 1 >>> a 7 """ "* YOUR CODE HERE *" a=1 while (n != 1): print (int(n)) a = a + 1 if n % 2 == 0: n = n / 2 else: n = n * 3 + 1 print (int(n)) return int(a)

2025年python编程 cs61A笔记01-02

What is Computer Science?

print输出

习题及答案：

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