Python For Loop无法运行

Question

I'm trying to run a for loop inside of a while loop, but for some reason it's not being run at all.

Here's the code:

with open("Nominees_18.csv") as nominees:
    reader = csv.reader(nominees)
    next(reader)
    for c, row in enumerate(reader):
        print(row[0], row[1], c)
    while True:
        name = input("chose a number")
        print(4)
        for c, row in enumerate(reader):
            print(4)
            if str(c) in name:
                print(len([i for i in row if row[i] == "y"]))
        if input("chose another?") == ("no" or "No"):
            break

The script asks you for a number, then asks if you want to choose another number. I put print(4) to test the for loop and it doesn't come up.

There's further code above this but I haven't included it as I don't think it's relevant, but if you want it, then let me know.

I have no idea why this could be happening.

Thanks.

Answer 1

input() waits until the user has entered something, so your print(4) is executed after the user presses enter. Your for loop inside of the while loop might not find anything because you have already iterated over your file contents before (and the reader is at the end of the file already). You might want to save your file content in a local variable (in a parsed form) so that you can search through it more easily, if the file is not too large.

Answer 2

The generator is already exhausted once it was enumerated in the first loop. Trying to call the next() method on it after the first loop will result in StopIteration error, but trying to iterate over it in the next for loop won't just do anything as it is already empty.