There was a long thread last year on a subject, titled "Dictionary
destructing and unpacking.":
https://mail.python.org/pipermail/python-ideas/2017-June/045963.html
You might want to read through it and see what ideas and problems were
raised then.
In that discussion, there's also a link to an older pattern matching thread:
https://mail.python.org/pipermail/python-ideas/2015-April/032907.html
Eric
On 4/7/2018 1:26 PM, thautwarm wrote:
We know that Python support the destructing of iterable objects.
m_iter= (_for _in range(10))
a,*b, c= m_iter
That's pretty cool! It's really convenient when there're many corner
cases to handle with iterable collections.
However destructing in Python could be more convenient if we support
dictionary destructing.
In my opinion, dictionary destructing is not difficult to implement and
makes the syntax more expressive. A typical example is data access on
nested data structures(just like JSON), destructing a dictionary makes
the logic quite clear:
data= {
"direct": "some data",
"nested": {
"lst_data": [1,2,3],
"int_data": 1
}
}
{
"direct": direct,
"nested": {
"lst_data": [a, b, c],
}
}= data
Dictionary destructing might not be very well-known but it really helps.
The operations on nested key-value collections are very frequent, and
the codes for business logic are not readable enough until now. Moreover
Python is now popular in data processing which must be enhanced by the
entire support of data destructing.
Here are some implementations of other languages:
Elixir, which is also a popular dynamic language nowadays.
|iex> %{} = %{:a => 1, 2 => :b} %{2 => :b, :a => 1} iex> %{:a => a} =
%{:a => 1, 2 => :b} %{2 => :b, :a => 1} iex> a 1 iex> %{:c => c} = %{:a
=> 1, 2 => :b} ** (MatchError) no match of right hand side value: %{2 =>
:b, :a => 1}|
And in F#, there is something similar to dictionary
destructing(actually, this destructs `struct` instead)
type MyRecord = { Name: string; ID: int } letIsMatchByName record1
(name: string) = matchrecord1 with| { MyRecord.Name = nameFound;
MyRecord.ID = _; } whennameFound = name -> true| _ -> falseletrecordX =
{ Name = "Parker"; ID = 10} letisMatched1 = IsMatchByName recordX
"Parker"letisMatched2 = IsMatchByName recordX "Hartono"
All of them partially destructs(or matches) a dictionary.
thautwarm
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