Summary  
Local vs. global variables define the scope and lifetime of data in code, where global variables are accessible throughout the entire program and local variables exist only within the function or block in which they are declared.

General domain of usage  
Software development (managing variable scope in code modules)


import unittest
import user_code
import ast
import re   
import importlib
import csv
import unittest
import importlib
import sys
import io

class TestTask(unittest.TestCase):
    def test_global_x_modified(self):
        import user_code
        importlib.reload(user_code)
        x_value = getattr(user_code, 'x', None)
        _dynamic_test(
            self,
            x_value == 20,
            "Global variable x was correctly changed to 20.",
            f"Expected global x to be 20, got {x_value}",
        )

    def test_local_y_not_global(self):
        import user_code
        importlib.reload(user_code)
        has_y = hasattr(user_code, 'y')
        _dynamic_test(
            self,
            not has_y,
            "Local variable y is not accessible outside the function.",
            "Variable y should not be defined globally.",
        )

    def test_return_string_content(self):
        import user_code
        importlib.reload(user_code)
        output = getattr(user_code, 'output', None)
        expected = "x is 20, y is 5"
        _dynamic_test(
            self,
            isinstance(output, str) and output.strip() == expected,
            f"Returned string is correct: '{expected}'",
            f"Expected return string '{expected}', got '{output}'",
        )

    def test_x_printed_value(self):
        import user_code
        importlib.reload(user_code)
        f = io.StringIO()
        sys_stdout = sys.stdout
        sys.stdout = f
        importlib.reload(user_code)
        sys.stdout = sys_stdout
        output = normalize_text(f.getvalue())
        _dynamic_test(
            self,
            "20" in output,
            "Printed output includes updated value of x.",
            f"Expected to see '20' printed in output, got: {output}",
        )

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)

def normalize_text(text):
    text = text.lower()
    text = re.sub(r"\\s{2,}", " ", text)
    text = re.sub(r"\\s*([,:?])\\s*", r"\\1 ", text)
    return text.strip()

def change_var(code: str, var_name: str, value: str) -> str:
    tree = ast.parse(code)
    lines = code.splitlines()
    changed = False
    # Collect all assignment nodes to modify
    assign_nodes = [
        (i, node)
        for i, node in enumerate(tree.body)
        if isinstance(node, ast.Assign)
        and any(isinstance(target, ast.Name) and target.id == var_name for target in node.targets)
    ]

    # If nothing to change, return unmodified code
    if not assign_nodes:
        return code

    # Perform replacements for all matching assignments (from last to first to not break line offsets)
    for i, node in reversed(assign_nodes):
        start_line = node.lineno - 1
        line = lines[start_line]
        indent = ' ' * (len(line) - len(line.lstrip()))
        lines[start_line] = f"{indent}{var_name} = {value}"
        next_line = len(lines)
        for next_node in tree.body[i+1:]:
            if hasattr(next_node, 'lineno'):
                next_line = next_node.lineno - 1
                break
        if next_line > start_line + 1:
            lines[start_line+1:next_line] = []
        changed = True

    return '\\n'.join(lines) if changed else code

if __name__ == "__main__":
    unittest.main()


test_main.py

Apprendere le tecniche di packing/unpacking, argomenti flessibili per le funzioni, funzioni di ordine superiore, lambda, ambito delle variabili, closure, iteratori e decorator. Progettato per chi ha completato un corso introduttivo di Python e desidera scrivere codice più efficiente, espressivo e potente.

Esplora l'arte del packing e unpacking di liste, tuple e dizionari per scrivere codice Python più espressivo ed efficiente.

Esplora il mondo delle funzioni di ordine superiore, il passaggio di funzioni come argomenti e la scrittura di funzioni anonime concise con lambda.

Svela i misteri dell'ambito delle variabili e scopri come le funzioni annidate e le closure consentano un'incapsulamento potente.

Approfondimento sul protocollo di iterazione di Python, iteratori personalizzati e funzioni generatrici per un'elaborazione efficiente dei dati.

Variabili Locali vs. Globali

Soluzione