Python while while循环用于重复指数后退

Question

我写了一个函数,应该多次尝试一个函数,直到这个工作.

def Retry(attempts,back_off,value):
    for i in range(attempts):
        counter = 0
        while attempts > counter:
            try:
                x = function(value)
            except:
                counter =+ 1
                delay = (counter * back_off) + 1
                print ('trying again in {} seconds'.format(delay))
                sleep(delay)
                continue
            break
        return x

result = Retry(20,2,value)

每次失败的尝试之后都应该是指数增长的时间间隔,即2秒后的第二次尝试,4秒后的第三次尝试,8秒后的第四次尝试,依此类推.问题在于,在我写的函数中,如果第一次尝试失败,我只会得到一系列无限的行:

trying again in 3 seconds
trying again in 3 seconds
trying again in 3 seconds
trying again in 3 seconds
trying again in 3 seconds
trying again in 3 seconds
....

我究竟做错了什么？为什么循环堆栈在那里？

Answer 1

该

counter =+ 1

应该

counter += 1