arr = [] num = 0 sum = 0 while 1: val = input('请输入一个数') try: if val == 'done': for i in arr: sum = sum + float(i) print('总和为:' + str(sum)) print('输入个数为:' + str(num)) print('平均数为:' + str(sum/num)) exit() else: float(val) arr.append(float(val)) num = num + 1 except(ValueError): print('这不是一个数字') print(ValueError) pass追问