带时间的进度条

导入time模块来计算代码运行的时间，加上代码迭代进度使用格式化字符串来输出代码运行进度

 1 import time
 2 scale = 50
 3 print("执行开始，祈祷不报错".center(scale // 2,"-"))
 4 start = time.perf_counter()
 5 for i in range(scale + 1):
 6     a = "*" * i
 7     b = "." * (scale - i)
 8     c = (i / scale) * 100
 9     dur = time.perf_counter() - start
10     print("
{:^3.0f}%[{}->{}]{:.2f}s".format(c,a,b,dur),end = "")
11     time.sleep(0.1)
12 print("
"+"执行结束，万幸".center(scale // 2,"-"))