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PL/pgSQL control structures for lists / arrays


PL/pgSQL control structures for lists / arrays

By : Urvin
Date : November 21 2020, 01:01 AM
it should still fix some issue Is it possible to use something like this in Postgres? This is the example from PL/SQL what I want to do: ,
code :
CREATE OR REPLACE FUNCTION CREATE_PAYMENT(p_amount_list numeric[])
  RETURNS numeric AS
$func$
DECLARE
   s_chk_amnt numeric := 0; -- init variable!
   r          numeric;
BEGIN
-- IF p_amount_list <> '{}' THEN  -- just noise
   FOREACH r IN ARRAY p_amount_list
   LOOP
      s_chk_amnt := s_chk_amnt + r;
   END LOOP;
-- END IF;

RETURN s_chk_amnt;
END
$func$ LANGUAGE plpgsql
SELECT sum(elem) AS sum_amount
FROM   unnest(p_amount_list) elem;


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Data Structures in Java & Python and their implementations: Lists, Arrays, Tuples

Data Structures in Java & Python and their implementations: Lists, Arrays, Tuples


By : Jason E. Rist
Date : March 29 2020, 07:55 AM
Hope that helps Most of that is wrong.
The list abstract data type is an ordered sequence of elements, allowing duplicates. There are many ways to implement this data type, particularly as a linked list, but most programming languages use dynamically resized arrays. Even linked lists may support indexing. There is no way for the implementation to skip directly to the n'th element, but it can just follow links to get there. Java's List type does not specify an implementation, only an interface. The ArrayList type is a List implemented with a dynamic array; the Linkedlist is exactly what the name says. Python's lists are implemented with dynamically resized arrays. Python's tuples are implemented with fixed-size arrays. There are actually two Python types commonly referred to as arrays, not counting the common newbie usage of "array" to refer to Python lists. There are the arrays provided by the array module, and there are NumPy's ndarrays. When you index an array, the implementation does not iterate from the location of the first element to the n'th. It adds an offset to the address of the array to skip to the element directly, without iterating.
Data Structures: If Heaps are trees, why are they implemented internally with Lists or arrays?

Data Structures: If Heaps are trees, why are they implemented internally with Lists or arrays?


By : Jim Foye
Date : March 29 2020, 07:55 AM
hope this fix your issue TL;DR: Save on memory overhead, get more speed from data locality.
For a binary tree you need in each node 4 bytes for left child and 4 byte for the right child (or 8+8 if you are on 64 bit system). That's just the bare pointers you need. If you store a 32 bit int that's a lot of overhead. Add another pointer for the parent that is needed for pushing a node towards the root and you are looking at 24 bytes of overhead for a 4 byte integer on a 64bit system.
How to implement Structures of Arrays instead of Arrays of Structures in Fortran?

How to implement Structures of Arrays instead of Arrays of Structures in Fortran?


By : Stefan Cirlig
Date : March 29 2020, 07:55 AM
I wish this helpful for you I'm writing my code on CFD topic with Fortran. After discussing with some friends from computer science, they told me that one could speed up the computation time if one implements Structures of Arrays (SoA) instead of Arrays of Structures (AoS) on his/her code. , There is really nothing difficult about this concept.
Instead of
code :
type struct
  real x, y, z
end type

type(struct), allocatable :: array(:)
type(struct2)
  real, dimension(:), allocatable :: x, y, z
end ype

type(struct2) :: arrays
real x(bigN)
real y(bigN)
real z(bigN)
Weird problem with lists structures and arrays

Weird problem with lists structures and arrays


By : user2636861
Date : March 29 2020, 07:55 AM
hope this fix your issue Your Node contains a list. This is a C++ class with its own non-trivial state. The difference between Node node_array[5]; and calloc(5, sizeof(Node) ) is that the first one will actually call the constructors properly. The code bombs when trying to copy this badly initialized list somewhere else. If you want a dynamic allocation, use new Node[5] instead.
Arrays, linked lists and other data structures in cmd.exe (batch) script

Arrays, linked lists and other data structures in cmd.exe (batch) script


By : MS Guru
Date : March 29 2020, 07:55 AM
hop of those help? Ok. I'll try to be as clear as possible to not be misunderstood...
In Windows Batch files a variable name should begin with a letter and may include any valid character, where valid characters are: #$'()*+,-.?@[]_`{}~ besides letters and digits.
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