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 expdef 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 expdef add_sub(exp):
    ret = re.findall('[+-]?\d+(?:\.\d+)?',exp)
    sum = 0
    for i in ret:
        sum += float(i)
    return sumdef 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))