Python编程 基础练习(一)

from datetime import datetime

# 求多少以内的素数
n = 100000
count = 0
start = datetime.now()
for i in range(2, n + 1):
    for j in range(2, i):
        if i % j == 0:   # 是合数
            break
    else:  # 是素数
        count += 1
        # print(i, end=" ")

delta = (datetime.now() - start).total_seconds()
print(count, "\n用时：{}s".format(delta))

from datetime import datetime
# 求多少以内的素数
n = 100000
count = 1   # 2是素数
start = datetime.now()
for i in range(3, n + 1, 2):   # 大于2的偶数不可能是素数了
    for j in range(3, int(i ** 0.5) + 1, 2):
        if i % j == 0:  # 是合数
            break
    else:   # 是素数
        count += 1
        # print(i, end=" ")
delta = (datetime.now() - start).total_seconds()
print(count, "\n用时：{}s".format(delta))

n = int(input("打印几行："))
e = n // 2
for i in range(-e, n-e):
    print(" " * abs(i) + "*" * (n - 2 * abs(i)))

row = int(input('打印杨辉三角前几行：'))


def print_triangle(x):    # 打印几行
    tri = [1]    # 当前行所有元素
    pre = [1]    # 上一行所有元素
    n = 1
    while n <= x:
        yield tri   # yield生成器函数  返回
        for i in range(1, len(pre)):
            # 中间的各个元素值 = 上一行相应位置的值 + 与前一位置元素的值
            tri[i] = pre[i-1] + pre[i]
        # 每次计算完列表tri中的元素之后，通过append(1)来添加末尾的1
        tri.append(1)
        # 得到后，传给上行
        pre = tri[:]
        n += 1


trianges = print_triangle(row)   # 传入参数
for item in trianges:
    print(item)

运行结果如下：
打印杨辉三角前几行：5
[1]
[1, 1]
[1, 2, 1]
[1, 3, 3, 1]
[1, 4, 6, 4, 1]

def fibonacii(n):
    if n <= 1:  # 0 1
        return n
    else:
        return (fibonacii(n - 1) + fibonacii(n - 2))


x = int(input("输出前几项?: "))
if x <= 0:
    print("请输入输入正数！")
else:
    print("斐波那契数列前{}项:".format(x), end=" ")
    for i in range(1, x + 1):
        print(fibonacii(i), end=" ")

print("水仙花数：", end=" ")
for i in range(100, 1000):   # 三位数
    if i == sum([int(x) ** 3 for x in str(i)]):  # 求水仙花数
        print(i, end=" ")
    else:
        continue

import random

num = int(input("请输入注数："))
print("*" * 16 + " 双色球 {} 注 ".format(num) + "*" * 16)

for i in range(num):
    flag = True
    red_ball_list = []
    while flag:
        # 红球 1-33中选
        red_ball = random.randint(1, 33)
        if red_ball not in red_ball_list:
            # 个位数的  前面加个0  变字符串
            if red_ball < 10:
                red_ball = "0{}".format(red_ball)
                red_ball_list.append(red_ball)
            else:
                red_ball_list.append(str(red_ball))
        # 选出6个不重复的红球号码
        if len(red_ball_list) == 6:
            flag = False
    # 蓝球  1-16中选
    blue_ball = random.randint(1, 16)
    if blue_ball < 10:
        blue_ball = "0{}".format(blue_ball)
    else:
        blue_ball = str(blue_ball)
    print("红球：" + " ".join(red_ball_list, ) + "   蓝球：" + blue_ball)

print("*" * 45)