python - ValueError：以 10 为底的 long() 的无效文字：''

Question

我怎样才能让它工作？

n = 1234
f = open("file", "r")
while True:
 x=f.readline()
 print "*********************"
 print n%(long(x))
 if n%(long(x))==0:
   print x
else:
 print "..."

我是 python 的菜鸟，我遇到了一个我不明白的错误。我究竟做错了什么？

ValueError: invalid literal for long() with base 10: ''

Answer 1

In [104]: long('')
ValueError: invalid literal for long() with base 10: ''

This error is telling you that x is the empty string.

You could be getting this at the end of the file. It can be fixed with:

while True:
    x = f.readline()
    if x == '': break

Answer 2

块可以是调试此类事情的try/except便捷方式

n = 1234
f = open("file", "r")
while True:
 x=f.readline()
 print "*********************"
 try:                                              # Add these 3 lines
     print n%(long(x))
 except ValueError:                                # to help work out
     print "Something went wrong {!r}".format(x)   # the problem value
 if n%(long(x))==0:
   print x
else:
 print "..."