从函数返回哈希的最佳Perl练习是什么？ [英] What's the best Perl practice for returning hashes from functions?

问题描述

我正在研究传递函数返回数据的散列引用的最佳做法。

一方面，仅将输入值传递给函数并且只返回输出变量似乎很直观。但是，在Perl中传递哈希只能通过引用完成，所以它有点混乱，看起来更像是一个犯错的机会。

另一种方法是在输入变量中传递一个引用，但是它必须在函数中处理，并且可能不清楚输入是什么什么是返回变量。

对此的最佳实践是什么？

返回对数组和散列的引用，然后解引用<$ p
$ b

 （$ ref_array，$ ref_hash）= $ this-> getData（'input'）; 
 @array = @ {$ ref_array}; 
％hash =％{$ ref_hash}; 
  

将引用（@array，％hash）传递给将保存输出数据的函数。 / p>

  $ this-> getData（'input'，\ @ array，\％hash）; 
  

解决方案

只需返回参考。无需像您在示例中那样对整个
散列进行解引用。

  my $ result = some_function_that_returns_a_hashref ; 
表示Foo is，$ result-> {foo};对于键％$ result，
表示$ _，=>，$ result-> {$ _}; 
  

等。

我从未见过任何人通过空引用来保存结果。这是Perl，而不是C。

I am mulling over a best practice for passing hash references for return data to/from functions.

On the one hand, it seems intuitive to pass only input values to a function and have only return output variables. However, passing hashes in Perl can only be done by reference, so it is a bit messy and would seem more of an opportunity to make a mistake.

The other way is to pass a reference in the input variables, but then it has to be dealt with in the function, and it may not be clear what is an input and what is a return variable.

What is a best practice regarding this?

Return references to an array and a hash, and then dereference it.

($ref_array,$ref_hash) = $this->getData('input');
@array = @{$ref_array};
%hash = %{$ref_hash};

Pass in references (@array, %hash) to the function that will hold the output data.

$this->getData('input', \@array, \%hash);

解决方案

Just return the reference. There is no need to dereference the whole hash like you are doing in your examples:

my $result = some_function_that_returns_a_hashref;
say "Foo is ", $result->{foo};
say $_, " => ", $result->{$_} for keys %$result;

etc.

I have never seen anyone pass in empty references to hold the result. This is Perl, not C.

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