如何在 python 中使用 enumerate() 枚举字典中的项目

Question

As the title suggests I wanted to enumerate the key and its values (without brackets) in python. I tried the following code:

example_dict = {'left':'<','right':'>','up':'^','down':'v',}
[print(i,j,a) for (i,j,a) in enumerate(example_dict.items())]

But it doesn't work. I want the output to be like this

0 left <
1 right >
2 up ^
3 down v

Thank you in advance

Answer 1

In this case enumerate returns (index, (key, value)) , so you just need to change your unpacking to for i, (j, a) , though personally I would use k, v instead of j, a in an example.

for i, (k, v) in enumerate(example_dict.items()):
    print(i, k, v)

BTW, don't use a comprehension for side effects ; just use a for-loop.

Answer 2

As in Alexandre's comment, the code would work like this:

for (i, (name, sym)) in enumerate(example_dict.items()):
    print(i, name, sym)

A comment about style: while comprehension is really neat when computing values, using it for a loop of printing would work, but would obfuscate the intent of your code, making it less readable.