我在 python 3 中遇到关于 Keyerror 的错误

Question

I got this code from udemy course:

    def choose_magic(self):
     i = 1
     print(bcolors.OKBLUE + bcolors.BOLD + "Magic" + bcolors.ENDC)
     for spell in self.magic:
        print(str(i) + ":", spell["name"], "(cost:", str(spell["cost"]) + ")")
        i += 1

When I try to call this function I got this error:

print(str(i) + ":", spell["name"], "(cost:", str(spell["cost"]) + ")")
KeyError: 'cost'

I got this from udemy course and when I try to run return that error.

Answer 1

The spell dict doesn't have a "cost" key. You'll need to look at where it's initialized (ie the members of self.magic ).

FWIW, this print statement:

print(str(i) + ":", spell["name"], "(cost:", str(spell["cost"]) + ")")

works a lot better in Python 3 as an f-string:

print(f"{i}: {spell['name']} (cost: {spell['cost']})")

but you still need to sort out that cost thing before it'll work. :)