Is it possible to add pair at the end of the

问题:

When I introduce new pair it is inserted at the beginning of dictionary. Is it possible to append it at the end?

回答1:

UPDATE

As of Python 3.7, dictionaries remember the insertion order. By simply adding a new value, you can be sure that it will be "at the end" if you iterate over the dictionary.

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Dictionaries have no order, and thus have no beginning or end. The display order is arbitrary. If you need order, you can use a list of tuples instead of a dict:

In [1]: mylist = []

In [2]: mylist.append(('key', 'value'))

In [3]: mylist.insert(0, ('foo', 'bar'))

You'll be able to easily convert it into a dict later:

In [4]: dict(mylist)
Out[4]: {'foo': 'bar', 'key': 'value'}

Alternatively, use a collections.OrderedDict as suggested by IamAlexAlright.

回答2:

A dict in Python is not "ordered" - in Python 2.7+ there's collections.OrderedDict, but apart from that - no... The key point of a dictionary in Python is efficient key->lookup value... The order you're seeing them in is completely arbitrary depending on the hash algorithm...

回答3:

No. Check the OrderedDict from collections module.

回答4:

dictionary data is inorder collection if u add data to dict use this : Adding a new key value pair

Dic.update( {'key' : 'value' } )

If key is string you can directly add without curly braces

Dic.update( key= 'value' )