为什么文件没有打开？ （蟒蛇）

Question

Whenever I try to input "C.elegans_small.gff", the program gives the print statement of "unable to open". However, I want it to open. Why is this happening?

print("Gene length computation for C. elegans.")
print()
file1 = "C.elegans_small.gff"
file2 = "C.elegans.gff"
user_input = input("Input a file name: ")
while user_input != file1 or user_input != file2:
    print("Unable to open file.") 
    user_input = input("Input a file name: ")
    if user_input == file1 or user_input == file2:
        break

Answer 1

Your code is incorrect because you are using or instead of and .

Let's say the user inputs file1 then the if-statement is False or True .

Since it is or and not and , if one of the statements is true it will still be in the while loop. The only way to break from the while loop is if the input is equal to file1 and file2 at the same time.

Here is a fixed version of your code when using and .

print("Gene length computation for C. elegans.")
print()
file1 = "C.elegans_small.gff"
file2 = "C.elegans.gff"
user_input = input("Input a file name: ")
while user_input != file1 and user_input != file2:
    #now if one is true it exits
    print("Unable to open file.") 
    user_input = input("Input a file name: ")

Also, this part is useless. This is because the while loop will check it and break by itself so you do not need an if statement to break it.

if user_input == file1 or user_input == file2:
        # This stays as or because if one is true you want it to pass
        break