实验四
实践任务1:
print(sum) sum = 42 print(sum) def inc(n): sum = n+1 print(sum) return sum sum = inc(7) + inc(7) print(sum)
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实践任务2.2:
list1 = [1, 9, 8, 4] print( sorted(list1) ) print( sorted(list1, reverse=True) ) print( sorted(list1, True) )
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实践任务2.3:
def func(a, b, c, /, *, d, e, f): return( [a,b,c,d,e,f] ) print(func(1,2,3,d=5,e=6,f=7))
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实践任务3:
def solve(a,b,c): delta=b*b-4*a*c delta_sqrt=abs(delta)**0.5 p1=-b/2/a p2=delta_sqrt/2/a if delta>=0: root1=p1+p2 root2=p1-p2 else: root1=complex(p1,p2) root2=complex(p1,-p2) return root1,root2 while True: try: a,b,c=eval(input('Enter eqution coefficient:')) if a==0: raise except: print('invalid input, or,a is zero') break else: root1,root2=solve(a,b,c) print(f'root1={root1:.2f},root2={root2:.2f}') print()
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实验任务4:
def list_generator(begin,end,step=1): x = [] i = begin while i >= begin and i<= end: x.append(i) i += step return x list1=list_generator(-5, 5) print(list1) list2=list_generator(-5, 5, 2) print(list2) list3=list_generator(1, 5, 0.5) print(list3)
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实践任务5:
def is_prime(n): if n < 2: return False for i in range(2,int(n**0.5)+1): if n % i == 0: return False return True h=[i for i in range(21)] for x in h[::2]: for a in range(0,21): if is_prime(a) is True: if is_prime(x-a) is True: print(f'{x}={a}+{x-a}') break else: a=1+a else: a=1+a
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实践任务6:
def encoder(strs): a=list(strs) i=0 while i <len(strs): b = ord(a[i]) if 65<=b<=85 or 97<=b<=117: c=chr(b+5) elif 85<=b<=90 or 117<=b<=122: c=chr(b-21) else: c=chr(b) a[i]=c i+=1 return ''.join(a) def decoder(strs): a = list(strs) i=0 while i < len(strs): b = ord(a[i]) if 70<=b<=90 or 102<=b<=122: c=chr(b-5) elif 65<=b<=70 or 97<=b<=102: c=chr(b+21) else: c=chr(b) a[i] = c i+=1 return ''.join(a) a=input('输入英文文本: ') print(f'编码后的文本:{encoder(a)}') print(f'对编码后的文本解码:{decoder(encoder(a))}')
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实践任务7:
def collatz(n): x=[n] while n!=1: if n%2==0: n=n/2 else: n=3*n+1 x.append(int(n)) return x try: n=int(input('Enter a positive integer:')) if n<=0: raise except: print('Error: must be a positive integer') else: print(collatz(n))
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