为什么对 zip() 调用的列表理解返回包含 zip object 的列表，而不是 zip() 的返回值列表？

Question

Playing around with python3 REPL and noticed the following:

Why are print( [zip([1,2,3], [3,1,4])] ) and print( list(zip([1,2,3], [3,1,4])) ) different?

The first returns [<zip object at 0xblah>] and the second returns [(1,3), (2,1), (3,4)] .

Trying to understand why the list comprehension in the first statement doesn't give me the result that the list() constructor gives - I think I'm confused about the difference between list comprehension and list() and would appreciate insight into what's happening under the hood.

Searching gives me this question on lists and tuples which doesn't answer my question.

Edit: A suggested question on The zip() function in Python 3 is very helpful background, but does not address the confusion in my question about the difference between a list comprehension and a list literal, so i prefer the submitted answer below as more complete.

Answer 1

The first statement is not a list comprehension, a list comprehension would give you the same result. It is just a list literal containing a zip object:

This would be a list comprehension:

[value for value in zip([1,2,3], [3,1,4])]

The above will print the same as list(zip([1, 2, 3], [3, 1, 4])) .

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In general, [something] means: A list with one element: something .

On the other hand, list(something) means: Iterate over the values in something, and make a list from the result. You can see the difference for example by putting primitive objects inside it, like a number:

>>> [2]
[2]
>>> list(2)
TypeError: 'int' object is not iterable