zip函数可为return语句存储多个输出

Question

def somefunction():
    outputs = []
    a = 0
    while a < 100:
        if a%2 == 0:
            b = 2*a + 1
            outputs.append(list(zip(a,b)))
        a += 1
    return outputs

The above code is not what i'm using exactly but produces the same error, why does the above code return:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
TypeError: zip argument #1 must support iteration

Is this a particularly efficient way of returning all the items within a function as one? If not, what is a better method?

Answer 1

It returns that error because of its exact error message; that is, the zip arguments must support iteration. You just have two numbers that you are trying to "store together". In that case, I'm assuming what you are looking for is the tuple data type. Either that or "put them together" with the list data type you already have. The zip is entirely unnecessary. I would suggest reading more about Python's built-in types .

Answer 2

Just get a list of tuples!! (or list if you prefer, but since you can't change tuples and you want to return all the outputs, tuples make more sense)

def somefunction():
    outputs = []
    a = 0
    while a < 100:
        if a%2 == 0:
            b = 2*a + 1
            tup = (a,b)
            outputs.append(tup)
        a += 1
    return outputs

There is no need to use zip here, zip is for joining two lists together, you only have two integers so you can store them in a tuple and then append the tuple to outputs

when zip would work for this

Zip would work if you stored all a s in a_list and all b s in b_list . Then you could do:

outputs.append(zip(a_list,b_list))

this is unnecessary because you can just append a and b together in a tuple to output just like my example. But that is how it would be done.

Answer 3

You can also use list comprehension in this case:

def f():
    return [(x, 2*x + 1) for x in range(100) if x%2 == 0]