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Mastering flat_map in Python with List Comprehension

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Introduction In Python, when working with nested lists or iterables, one common challenge is flattening them into a single list while applying transformations. Many programming languages provide a built-in flatMap function, but Python does not have an explicit flat_map method. However, Python’s powerful list comprehensions offer an elegant way to achieve the same functionality. This article examines implementation behavior using Python’s list comprehensions and other methods. What is flat_map ? Functional programming  flatMap is a combination of map and flatten . It transforms the collection's element and flattens the resulting nested structure into a single sequence. For example, given a list of lists, flat_map applies a function to each sublist and returns a single flattened list. Example in a Functional Programming Language: List(List(1, 2), List(3, 4)).flatMap(x => x.map(_ * 2)) // Output: List(2, 4, 6, 8) Implementing flat_map in Python Using List Comprehension Python’...

PL/SQL Sample code and error handling mechanism

SAMPLE PL/SQL


CREATE TABLE dummy
( dummy_value       VARCHAR2(1));
DECLARE
  -- Define local variable.
  my_string VARCHAR2(1) := ' ';
  my_number NUMBER;
BEGIN
  -- Select a white space into a local variable.
  SELECT ' ' INTO my_string FROM dummy;
  -- Attempt to assign a single white space to a number.
  my_number := TO_NUMBER(my_string);
EXCEPTION
 WHEN no_data_found THEN
   dbms_output.put_line('SELECT-INTO'||CHR(10)||SQLERRM);
END;
/

Output and Error:
The program returns the following output, which illustrates formatting user- defined exceptions. 

The CHR(10) inserts a line return and provides a clean break between the program's SQLCODE and SQLERRM messages:

RAISE my_error SQLCODE [1] 
SQLERRM [User-Defined Exception]

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