import random

num=input('請輸入你要生成的手機號個數:')
all_phone=[]
with open('phones.txt','a+') as f:
    count = 0
    while count<=int(num):
        start = '1891023'
        rand_num = str(random.randint(0, 9999))
        new_number = rand_num.zfill(4)
        phone_num = start + new_number
        if phone_num not
 
 in all_phone:
            all_phone.append(phone_num)
            count += 1
    for i in range(len(all_phone)):
        f.write(all_phone[i]+'\n')

優化生成手機號小程式：

1、.zfill是字串型別的方法所以要把隨機數轉成字串才可以使用該方法；隨機數不夠4位補0補夠4位；

2、把列表的值通過迴圈寫下標的方式寫入；