python 文件循环

Question

def main():    fileName = input ("What file are the numbers in? ")     infile = open (fileName, 'r' )    sum =0.0    count =0    line = infile.readline ( )     while line != " ":        sum=sum+eval(line)        count=count+1        line=infile.readline()    print ("\nThe average of the numbers is")main()What file are the numbers in? C:\Users\john\Documents\ze.txtTraceback (most recent call last):  File "C:/Users/john/AppData/Local/Programs/Python/Python36-32/s.py", line 12, in <module>    main()  File "C:/Users/john/AppData/Local/Programs/Python/Python36-32/s.py", line 8, in main    sum=sum+eval(line)  File "<string>", line 1        ^SyntaxError: unexpected EOF while parsing哪里出错了？是sum哪里吗，为什么错了？

Answer 1

   while line != " ": 

改成while line:就可以了，当读到eof时line为None。而不是空格