Online Learning Platform
Write a Python program that compares the memory size of a few objects.
True True
sys.getsizeof.import sys small, big = [], list(range(1000))print(sys.getsizeof(small) < sys.getsizeof(big))print(sys.getsizeof("") < sys.getsizeof("python"))True True
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Write a Python program that adds a folder to sys.path and imports a module from it.
Hello, SQA Tools!
import osimport sys os.makedirs("my_libs", exist_ok=True)with open(os.path.join("my_libs", "greetings.py"), "w") as f: f.write("def hello(name):\n return f'Hello, {name}!'\n") sys.path.append(os.path.abspath("my_libs"))import greetings print(greetings.hello("SQA Tools"))Hello, SQA Tools!
For real projects, install your package (pip install -e .) instead of changing sys.path.
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Write a Python program that checks whether a module has been imported yet.
False True
sys.modules holds every loaded module.import sys print("json" in sys.modules)import jsonprint("json" in sys.modules)False True
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Write a Python program that shows how many folders Python searches for modules.
list True True
sys.path is a list of folder names.import sys print(type(sys.path).__name__, len(sys.path) > 0)print(any("site-packages" in p for p in sys.path))list True True
The real folder names include your user name on most computers, so the program prints checks instead of the list.
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Write a Python program that prints a progress bar with sys.stdout.write.
#.... 20% ##... 40% ###.. 60% ####. 80% ##### 100%
write does not add a newline.import sys for step in range(1, 6): sys.stdout.write("#" * step + "." * (5 - step) + f" {step * 20}%\n")#.... 20% ##... 40% ###.. 60% ####. 80% ##### 100%
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Write a Python program that reads numbers from standard input and prints their total.
5, 10, 15 on separate lines
3 numbers, total 30
sys.stdin.import sys numbers = [int(line) for line in sys.stdin if line.strip()]print(len(numbers), "numbers, total", sum(numbers))3 numbers, total 30
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Write a Python program that writes normal output to stdout and errors to stderr.
stdout: report ready stderr: warning: 2 tests skipped
print(..., file=sys.stderr); run it and capture both streams separately.import subprocessimport sys code = "import sys\nprint('report ready')\nprint('warning: 2 tests skipped', file=sys.stderr)"r = subprocess.run([sys.executable, "-c", code], capture_output=True, text=True)print("stdout:", r.stdout.strip())print("stderr:", r.stderr.strip())stdout: report ready stderr: warning: 2 tests skipped
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Write a Python program that checks it is running on Python 3.10 or newer.
3 supported
sys.version_info with a tuple.import sys print(sys.version_info.major)print("supported" if sys.version_info >= (3, 10) else "please upgrade")3 supported
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Write a Python program that prints a different message per operating system.
Windows
sys.platform is “win32”, “linux” or “darwin”.import sys if sys.platform.startswith("win"): print("Windows")elif sys.platform == "darwin": print("macOS")else: print("Linux or another Unix")Windows
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Write a Python program that exits with code 1 on failure and show the code the caller sees.
['check.py', 'x'] -> 0 ok ['check.py'] -> 1 missing argument
sys.exit(1); the parent reads returncode.import subprocessimport sys with open("check.py", "w") as f: f.write("import sys\nif len(sys.argv) < 2:\n print('missing argument', file=sys.stderr)\n sys.exit(1)\nprint('ok')\n")for args in [["check.py", "x"], ["check.py"]]: r = subprocess.run([sys.executable, *args], capture_output=True, text=True) print(args, "->", r.returncode, (r.stdout or r.stderr).strip())['check.py', 'x'] -> 0 ok ['check.py'] -> 1 missing argument
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