
import unittest
import user_code
import ast
import re   
import importlib
import csv
import unittest
import importlib

class TestTask(unittest.TestCase):
    def test_generator_yields_all_lines(self):
        import user_code
        importlib.reload(user_code)
        log_lines = [
            "2024-06-01 12:00:01 INFO User logged in",
            "2024-06-01 12:00:03 ERROR Invalid password attempt",
            "2024-06-01 12:00:05 INFO User logged out",
            "2024-06-01 12:00:07 WARN Disk space low",
            "2024-06-01 12:00:10 INFO User logged in",
        ]
        gen = getattr(user_code, 'read_log_lines', None)
        _dynamic_test(
            self,
            callable(gen),
            "read_log_lines is defined as a function",
            "read_log_lines function is not defined",
        )
        result = gen(log_lines)
        _dynamic_test(
            self,
            hasattr(result, '__iter__') and hasattr(result, '__next__'),
            "read_log_lines returns a generator object",
            "read_log_lines does not return a generator object",
        )
        output = list(result)
        _dynamic_test(
            self,
            output == log_lines,
            "Generator yields all lines in correct order",
            f"Expected: {log_lines}, got: {output}",
        )

    def test_generator_is_lazy(self):
        import user_code
        importlib.reload(user_code)
        # Simulate a very large log file by using a custom list
        class BigLog:
            def __init__(self):
                self.yielded = 0
            def __len__(self):
                return 10**6
            def __getitem__(self, idx):
                self.yielded += 1
                return f"line {idx}"
        big_log = BigLog()
        gen = getattr(user_code, 'read_log_lines', None)
        _dynamic_test(
            self,
            callable(gen),
            "read_log_lines is defined as a function",
            "read_log_lines function is not defined",
        )
        result = gen(big_log)
        _dynamic_test(
            self,
            hasattr(result, '__iter__') and hasattr(result, '__next__'),
            "read_log_lines returns a generator object for large input",
            "read_log_lines does not return a generator object for large input",
        )
        # Only consume first 5 lines
        lines = []
        for i, line in enumerate(result):
            lines.append(line)
            if i == 4:
                break
        _dynamic_test(
            self,
            lines == [f"line {i}" for i in range(5)],
            "Generator yields first 5 lines correctly for large input",
            f"Expected first 5 lines, got: {lines}",
        )
        _dynamic_test(
            self,
            big_log.yielded == 5,
            "Generator is lazy and only accesses as many elements as needed",
            f"Generator accessed {big_log.yielded} elements, expected 5",
        )

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.

Challenge: Generator Functions

Soluzione