Python 练习实例19
Python 100例题目：一个数如果恰好等于它的因子之和，这个数就称为"完数"。例如6=1＋2＋3.编程找出1000以内的所有完数。
程序分析：请参照程序Python 练习实例14。
程序源代码：
实例(Python 2.0+)
#!/usr/bin/python
# -*- coding: UTF-8 -*-
from sys import stdout
for j in range(2,1001):
k = []
n = -1
s = j
for i in range(1,j):
if j % i == 0:
n += 1
s -= i
k.append(i)
if s == 0:
print j
for i in range(n):
stdout.write(str(k[i]))
stdout.write(' ')
print k[n]
以上实例输出结果为：
6 1 2 3 28 1 2 4 7 14 496 1 2 4 8 16 31 62 124 248
参考方法：
#!/usr/bin/env python # -*- coding: utf-8 -*- for i in range(1, 1001): sum = 0 for j in range(1, i): if i % j == 0: sum += j if sum == i: print(i)Python3 测试实例
#!/usr/bin/python3 list2 = [] for x in range(1, 1001): list1 = [] for i in range(1, int(x / 2) + 1): if x % i == 0: list1.append(i) if x == sum(list1): print(x) print(list1) list2.append(x) print("共计有%d个完数"%(len(list2)))参考方法：
#!/usr/bin/python # -*- coding: UTF-8 -*- __author__ = 'Arlene' def fun(num): sum = 1 # 1要加上，所以默认赋值为1 for i in range(2, num): # 因子不包括本身， if num % i == 0: sum += i if sum == num: return num result = [] for num in range(2, 1000): test = fun(num) if test: # 去掉空值 result.append(test) print("完数有：", result)参考方法：
#!/usr/bin/env python for i in range(1,1001): s = 0 L = [] for x in range(1,int((i+3)/2)): if i % x == 0: s += x L.append(x) if i == s: print(i) print(L)参考方法：
#!/usr/bin/env python # -*- coding: utf-8 -*- l = [] def num(n): for i in range(1,n + 1): if n != i and n % i == 0: l.append(i) return l for i in range(1,1001): sum = 0 l = [] m = num(i) if m == []: pass else: for j in m: sum += j if i == sum: print i参考方法：
#!/usr/bin/env python # -*- coding: utf-8 -*- list1 = [] for j in range(2, 10001): l = [] for i in range(1, j//2+1): if j % i == 0: l.append(i) if j == sum(l): list1.append(j) print("{}={}".format("+".join(map(str, l)), j))参考方法：
#!/usr/bin/python # -*- coding: UTF-8 -*- Sn = [] for i in range(2,1001): for j in range(1,i): if i % j == 0: Sn.append(j) if i == reduce(lambda x,y : x + y,Sn): print i,Sn Sn = []Python3 测试：
import functools for num in range(1,1001): savenum=int(num) list1 = [] for idx in range(1,int(num)): if num % idx == 0: list1.append(idx) if functools.reduce(lambda x,y:x+y,list1,0) == savenum: print(savenum,list1)参考：
import numpy as np for m in range(1,1001): n=[1] for i in range(2,m): if m % i == 0: n.append(i) if m == np.sum(n): print m,n