Python编程 基础练习（一）

1. 随机生成由2个大写字母（前2位）+2个小写字母（第3、4位）+4个数字（第5-8位）组成的密码（字符串）

import random

# 大写字母的ASCII码范围
a = [chr(i) for i in range(65, 91)]
# 小写字母的ASCII码范围
b = [chr(j) for j in range(97, 123)]
# 数字
c = [k for k in range(0, 10)]
s = ""
for x in range(1, 9):
    # 前两位 大写字母
    if x <= 2:
        s += random.choice(a)
    # 3、4位 小写字母
    elif 2 < x <= 4:
        s += random.choice(b)
    # 5-8位  数字  转成字符串
    else:
        s += str(random.choice(c))
print(s)

2. 编写函数，输出公式a+aa+aaa+…并计算其结果，其中a为1-9之间的整数，公式的项为n，如a和n分别为3和5时，输出并计算公式 3+33+333+3333+33333。

def analysis(a, n):
    s = ""
    for i in range(1, n + 1):
        if i == n:
            s += str(a) * i
        else:
            s += str(a) * i
            s = s + "+"
    print(s)   # 输出公式
    result = sum([int(str(a) * i) for i in range(1, n + 1)])  # 求和
    return result


a = int(input("输入a："))
n = int(input("输入n："))
print("计算结果为：{}".format(analysis(a, n)))

3. 统计一段英文字符串中单词"the"的个数，并提取出首字母非t的单词。

import re

_str = 'It was this sense of freedom the first innovation entrusted by the west life to the Individualism.' \
       ' On the other hand, American pioneers lost their comfortable life when they were trying to break ' \
       'away from the fetters of the old social order caused by the civilized society. Hence, they had to ' \
       'live by themselves with their independent spirit of pioneering .'

the_count = _str.count("the")  # "the" 的个数
print("单词the的个数：{}".format(the_count))

# 提取英文单词  "\b"表示单词的开头或结尾  返回列表
t_str = re.findall(r'\bt[a-zA-Z]+\b', _str)
all_str = re.findall(r'\b[a-zA-Z]+\b', _str)
print(all_str)  # 所有单词
print(t_str)    # 首字母含t的
no_t_str = []
for i in all_str:
    if i in t_str:  # 首字母是t的  滤掉
        continue
    else:
        no_t_str.append(i)
print(no_t_str)

4. 简单实现抽奖功能

import random

rewards ={"一等奖": "汽车一辆", "二等奖": "电视一台", "三等奖": "洗衣液一袋"}
print("一等奖---------->汽车一辆 \n二等奖---------->电视一台 \n三等奖---------->洗衣液一袋")


def getReward(rewards):
    num = random.random()
    if 0 <= num < 0.08:
        reward = "一等奖"
    elif 0.08 <= num < 0.3:
        reward = "二等奖"
    elif 0.3 <= num < 1:
        reward = "三等奖"
    # 返回对应奖项和奖项对应的值
    return reward, rewards[reward]


for i in range(3):
    order = input("按回车键抽奖...")
    k, v = getReward(rewards)
    print("第{}次抽奖结果：{}---->{}".format(i + 1, k, v))
    

5. 编写函数，接收一个任意字符串，返回其中最长的连续数字子串。

import re


def longest_num(s):
    # 匹配多个数字  返回一个列表
    nums = re.findall(r'\d+', s)
    _nums = [int(i) for i in nums]
    return max(_nums)   # 最长的


# 举例输入
# 123 python36a12345snfsig1?!132975..
# abcd12345ed125ss123456789
string = input("输入字符串为：")
result = longest_num(string)
print("最长的连续数字子串为：{}".format(str(result)))

6. 冒泡排序

nums = [1, 9, 8, 5, 6, 7, 4, 3, 2]
print("排序前：{}".format(nums))
length = len(nums)
for m in range(length - 1):
    flag = True
    for n in range(length - m - 1):
        if nums[n] > nums[n+1]:
            nums[n], nums[n+1] = nums[n+1], nums[n]
            flag = False
    if flag:
        break

print("排序后：{}".format(nums))