在Python中从单个元素列表中只获取元素？

Question

当已知Python列表总是包含单个项时，除了：

mylist[0]

你可能会问，'你为什么要这么做？‘。仅仅是好奇心。在Python中似乎有一种替代的方法来完成所有的事情。

Answer 1

singleitem, = mylist
# Identical in behavior (byte code produced is the same),
# but arguably more readable since a lone trailing comma could be missed:
[singleitem] = mylist

singleitem = next(iter(mylist))

singleitem = mylist.pop()

singleitem = mylist[-1]

for singleitem in mylist: break

# But also the only way to retrieve a single item and raise an exception on failure
# for too many, not just too few, elements as an expression, rather than a statement,
# without resorting to defining/importing functions elsewhere to do the work
singleitem = (lambda x: x)(*mylist)

还有许多其他的（结合或改变上面的部分，或者依赖于隐式迭代），但您明白了。