用Python编写简单的发红包程序和计算器原理

用Python编写简单的发红包程序：

第一种解法：数轴方法解决

import random

def red_packet(money,num):

    money = money * 100      #将钱数转换成分为单位

    ret = random.sample(range(1,money),num-1)    #在最低钱数1分与总钱数之间生成人数减1个数作为数轴的节点

    ret.sort()      #对列表进行排序

    ret.insert(0,0)

    ret.append(money)

    for i in range(len(ret)-1):

        yield (ret[i+1]-ret[i])/100

ret_g = red_packet(100,10)

for money in ret_g:

    print(money)

第二种解法：用概率解决

def red_packet(money,person):

    dic_person_money = {}

    for i in range(person):

        num = random.randint(1,100)

        dic_person_money['Person%s' % (i+1)] = num

    num_sum = 0

    for i in dic_person_money:

        num_sum += dic_person_money[i]

    for i in dic_person_money:

        x = round(dic_person_money[i]/num_sum*money,2)

        dic_person_money[i] = '$%s' % x

    return dic_person_money

result = red_packet(1,10)

print(result)

用Python设计一个简单的计算器：

import re

def atom_cal(exp):

    if '*' in exp:

        a,b = exp.split('*')

        return str(float(a)*float(b))

    elif '/' in exp:

        a, b = exp.split('/')

        return str(float(a) / float(b))

def format_exp(exp):

    exp = exp.replace('--','+')

    exp = exp.replace('+-', '-')

    exp = exp.replace('-+', '-')

    exp = exp.replace('++', '+')

    return exp

def mul_div(exp):

    while 1:

        ret = re.search('\d+(\.\d+)?[*/]-?\d+(\.\d+)?',exp)

        if ret:

            atom_exp = ret.group()

            res = atom_cal(atom_exp)

            exp = exp.replace(atom_exp,res)

        else:return exp

def add_sub(exp):

    ret = re.findall('[+-]?\d+(?:\.\d+)?',exp)

    sum = 0

    for i in ret:

        sum += float(i)

    return sum

def cal(exp):

    exp = mul_div(exp)

    exp = format_exp(exp)

    return add_sub(exp)

def main(exp):

    exp = exp.replace(' ','')

    while 1:

        ret = re.search('\([^()]+\)',exp)

        if ret:

            cal_exp = ret.group()

            res = str(cal(cal_exp))

            exp = exp.replace(cal_exp,res)

        else:break

    return cal(exp)

s = '1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )'

print(main(s))