Python3 里的 dict 是有序的吧？

[SimbaPeng]

t = {}

t['a'] = 'A'
t['b'] = 'B'
t['c'] = 'C'

for k, v in t.items():
print(v)

这个代码 j 结果在 py2.7 中是 ACB, 在 py3.6 中是 ABC.

而且我试了好多次 py3.6 的字典输出顺序跟存入顺序一样啊

[AX5N]

3.6 开始是有序的，之前是无序的

[Douglee]

那还要 collections.OrderedDict 有什么用..

[jimmyye]

https://docs.python.org/3.6/whatsnew/3.6.html#new-dict-implementation
> The order-preserving aspect of this new implementation is considered an implementation detail and should not be relied upon (this may change in the future, but it is desired to have this new dict implementation in the language for a few releases before changing the language spec to mandate order-preserving semantics for all current and future Python implementations; this also helps preserve backwards-compatibility with older versions of the language where random iteration order is still in effect, e.g. Python 3.5).

[264768502]

兼容性考虑

[laoyuan]

这个“序”如何访问呢？

[laoyuan]

如何根据序来访问呢？

[ipwx]

想要有序，请使用 collections.OrderedDict

[dd99iii]

t = {}

t['b'] = 'B'
t['a'] = 'A'
t['c'] = 'C'

for k, v in t.items():
print(v)

输出顺序跟存入顺序一样？你再试试

[lrxiao]

3.6 确保 dict 有序。。。但是你不能把这个当确保的事情

[lrxiao]

第一个确保 -> 实现

[zonghua]

tablib 里面用的好多

[SimbaPeng]

@dd99iii 一样啊，你自己用 3.6 试试

[dd99iii]

@SimbaPeng 诶。。嗯

https://stackoverflow.com/questions/39980323/dictionaries-are-ordered-in-python-3-6