（Python 3.x）语法从文件中读取一行时解析时出现EOF错误。

Question

(Python 3.x)So I keep getting a syntax error when reading a file. I've had this problem for a while now. I've been working on other parts of the program so far(not shown), but can't solve this syntax error. I am very confused. I feel guilty posting about a syntax error but I am out of ideas.

Here is the error: Syntax Error: unexpected EOF while parsing: , line 0, pos 0 @ line 8

Code:

def main(): 
    filename = 'p4input.txt'
    infile = open(filename, "r")
    command = 0
    while command != 3 and command < 3:
        command = eval(infile.readline()) #Problem here 
        convert = eval(infile.readline())
        print(command)

        print(convert)
    print("done")
main() 

The input file (p4input.txt) Has the following data:

2
534
1
1101

Complete traceback:
 Traceback (most recent call last):
      File "C:/Users/Ambrin/Desktop/CS 115/TESTER.py", line 16, in <module>
        main()
      File "C:/Users/Ambrin/Desktop/CS 115/TESTER.py", line 8, in <module>
        command = eval(infile.readline())
      File "<string>", line 0, in ?
    Syntax Error: unexpected EOF while parsing: <string>, line 0, pos 0

Answer 1

This is happening because when you get to the end of the file, readline() returns an empty string, so you're doing eval('') . You need to check for an empty string and break .

As pointed out in a comment above, you probably shouldn't be using eval . If all your inputs are expected to be integers, you can just use int() instead. You'll still need to check for '' though.