python - 基数为 10 的 int 的无效文字 : ''

Question

>>> n = ''.join(i for i in x if i.isdigit())
>>> n.isdigit()
True
>>> x.isdigit()
False

>>> previous = 0
>>> next = 100
>>> answer = 0


>>> for i in range(0,100):
...     answer += int(n[previous:next])
...     previous = next
...     next += 100
... 
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
ValueError: invalid literal for int() with base 10: ''

为什么我会收到这个错误？如您所见，n 是数字..

Answer 1

n 可能是数字，但在某个阶段你会超过 n 的长度，这样 n[previous:next]根本不包含任何字符。空字符串 '' 无法转换为 int，因此会出现说明完整情况的错误:invalid literal for int() with base 10: ''.

>>> int('')
Traceback (most recent call last):
  File "<input>", line 1, in <module>
ValueError: invalid literal for int() with base 10: ''