Working with dictionaries and keys

[wavic]

More of that. The order of the dict in Python 3.6 fallow the order of inserting its elements.

So, if you delete a key and it's value and insert again the same key with a new value they will be positioned after all the others when printing it.

In [1]: dict_ = {num: num**2 for num in range(2,5)}

In [2]: dict_
Out[2]: {2: 4, 3: 9, 4: 16}

In [3]: dict_.pop(3)
Out[3]: 9

In [4]: dict_
Out[4]: {2: 4, 4: 16}

In [5]: dict_[3] = 3**3

In [6]: dict_                 # here the order is preserved because of the interpreter. It's doing it
Out[6]: {2: 4, 3: 27, 4: 16}

In [7]: dict_[1] = 'one'

In [8]: dict_
Out[8]: {1: 'one', 2: 4, 3: 27, 4: 16} # the same  

In [9]: print(dict_)                          # but
{2: 4, 4: 16, 3: 27, 1: 'one'}