仅需5道题轻松掌握Python命令行相关标准库

仅需5道题轻松掌握Python命令行相关标准库 | Python技能树征题

0. 前言
1. 第 1 题：命令行日志记录
2. 第 2 题：将日志存储在磁盘上
3. 第 3 题：命令行参数解析
4. 第 4 题：运行系统命令
5. 第 5 题：命令行中进度条显示
试题代码地址

0. 前言

许多用户习惯于使用命令行工具与系统进行交互，因此 Python 中的提供了相应的标准库，用于向通过 shell 和文本与用户进行交互的软件提供常见方法和函数，我们就通过 5 道 Python 编程题来掌握 Python 相关标准库玩转命令行！

1. 第 1 题：命令行日志记录

知识点描述：使用 Python logging 模块记录运行信息。
问题描述：默认情况下 logging 模块只会输出错误信息，如何使 logging 记录程序运行中包括警告等更普通的运行信息，请从以下选项中选出你认为正确的答案：
A.

import logging, sys
logging.basicConfig(level=logging.INFO, stream=sys.stderr, format='%(asctime)s %(name)s %(levelname)s %(message)s')
log = logging.getLogger(__name__)
def my_add(a, b, weight=1):log.info('Starting add')if a == b == 0:log.warning('Warning! 0 for any one')res = (a + b) * weightlog.info('(%s + %s) * %s = %s' % (a, b, weight, res))print(res)
if __name__ == '__main__':my_add(5, 3)my_add(0, 0)

import logging, sys
logging.basicConfig(level=logging.ERROR, stream=sys.stderr, format='%(asctime)s %(name)s %(levelname)s %(message)s')
log = logging.getLogger(__name__)
def my_add(a, b, weight=1):log.info('Starting add')if a == b == 0:log.warning('Warning! 0 for any one')res = (a + b) * weightlog.info('(%s + %s) * %s = %s' % (a, b, weight, res))print(res)
if __name__ == '__main__':my_add(5, 3)my_add(0, 0)

import logging, sys
logging.basicConfig(level=logging.NOTSET, stream=sys.stderr, format='%(asctime)s %(name)s %(levelname)s %(message)s')
log = logging.getLogger(__name__)
def my_add(a, b, weight=1):log.info('Starting add')if a == b == 0:log.warning('Warning! 0 for any one')res = (a + b) * weightlog.info('(%s + %s) * %s = %s' % (a, b, weight, res))print(res)
if __name__ == '__main__':my_add(5, 3)my_add(0, 0)

import logging, sys
logging.basicConfig(level=logging.WARN, stream=sys.stderr, format='%(asctime)s %(name)s %(levelname)s %(message)s')
log = logging.getLogger(__name__)
def my_add(a, b, weight=1):log.info('Starting add')if a == b == 0:log.warning('Warning! 0 for any one')res = (a + b) * weightlog.info('(%s + %s) * %s = %s' % (a, b, weight, res))print(res)
if __name__ == '__main__':my_add(5, 3)my_add(0, 0)

正确答案： A

2. 第 2 题：将日志存储在磁盘上

知识点描述：将日志信息写入磁盘文件中。
问题描述：编写斐波那契计算函数，并用日志文件记录计算出的数字以及运行时间，请从以下选项中选出你认为正确的答案：
A.

import logging, sys
import datetime
def f(n):log.info('Computing up to %sth fibonacci number', n)a, b = 0, 1for n in range(n):a, b = b, a+bprint(b, '', end='')print(b)
logging_file = 'log.txt'
logging.basicConfig(level=logging.WARN, filename=logging_file, format='%(asctime)s %(name)s %(levelname)s: %(message)s')
log = logging.getLogger(__name__)
if __name__ == '__main__':f(datetime.datetime.now().second)

import logging, sys
import datetime
def f(n):log.info('Computing up to %sth fibonacci number', n)a, b = 0, 1for n in range(n):a, b = b, a+bprint(b, '', end='')print(b)
logging_file = 'log.txt'
logging.basicConfig(level=logging.WARN, format='%(asctime)s %(name)s %(levelname)s: %(message)s')
log = logging.getLogger(__name__)
if __name__ == '__main__':f(datetime.datetime.now().second)

import logging, sys
import datetime
def f(n):log.info('Computing up to %sth fibonacci number', n)a, b = 0, 1for n in range(n):a, b = b, a+bprint(b, '', end='')print(b)
logging_file = 'log.txt'
logging.basicConfig(level=logging.INFO, filename=logging_file, format='%(asctime)s %(name)s %(levelname)s: %(message)s')
log = logging.getLogger(__name__)
if __name__ == '__main__':f(datetime.datetime.now().second)

import logging, sys
import datetime
def f(n):a, b = 0, 1for n in range(n):a, b = b, a+bprint(b, '', end='')print(b)
logging_file = 'log.txt'
logging.basicConfig(level=logging.INFO, filename=logging_file, format='%(asctime)s %(name)s %(levelname)s: %(message)s')
log = logging.getLogger(__name__)
if __name__ == '__main__':f(datetime.datetime.now().second)

正确答案： C

3. 第 3 题：命令行参数解析

知识点描述：编写命令行工具，根据提供给脚本的选项参数改变程序行为。
问题描述：编写命令行工具，根据提供给脚本的选项参数可以运行多个数据间的加/减/乘/除，请从以下选项中选出你认为正确的选项：
A.

import argparse
import operator
import logging
import functools
parser = argparse.ArgumentParser(description='Applies an operation to one or more numbers')
parser.add_argument("number", help="One or more numbers to perform an operation on.", type=int)
parser.add_argument('-o', '--operation', help="The operation to perform on numbers.", choices=['add', 'sub', 'mul', 'div'], default='add')
parser.add_argument("-v", "--verbose", action="store_true", help="increase output verbosity")
opts = parser.parse_args()
logging.basicConfig(level=logging.INFO if opts.verbose else logging.WARNING)
log = logging.getLogger()
operation = getattr(operator, opts.operation)
log.info('Applying %s to %s', opts.operation, opts.number)
print(functools.reduce(operation, opts.number))

import argparse
import operator
import logging
import functools
parser = argparse.ArgumentParser(description='Applies an operation to one or more numbers')
parser.add_argument("number", help="One or more numbers to perform an operation on.", nargs='+')
parser.add_argument('-o', '--operation', help="The operation to perform on numbers.", choices=['add', 'sub', 'mul', 'div'], default='add')
parser.add_argument("-v", "--verbose", action="store_true", help="increase output verbosity")
opts = parser.parse_args()
logging.basicConfig(level=logging.INFO if opts.verbose else logging.WARNING)
log = logging.getLogger()
operation = getattr(operator, opts.operation)
log.info('Applying %s to %s', opts.operation, opts.number)
print(functools.reduce(operation, opts.number))

import argparse
import operator
import logging
import functools
parser = argparse.ArgumentParser(description='Applies an operation to one or more numbers')
parser.add_argument("number", help="One or more numbers to perform an operation on.", nargs='2', type=int)
parser.add_argument('-o', '--operation', help="The operation to perform on numbers.", choices=['add', 'sub', 'mul', 'div'], default='add')
parser.add_argument("-v", "--verbose", action="store_true", help="increase output verbosity")
opts = parser.parse_args()
logging.basicConfig(level=logging.INFO if opts.verbose else logging.WARNING)
log = logging.getLogger()
operation = getattr(operator, opts.operation)
log.info('Applying %s to %s', opts.operation, opts.number)
print(functools.reduce(operation, opts.number))

import argparse
import operator
import logging
import functools
parser = argparse.ArgumentParser(description='Applies an operation to one or more numbers')
parser.add_argument("number", help="One or more numbers to perform an operation on.", nargs='+', type=int)
parser.add_argument('-o', '--operation', help="The operation to perform on numbers.", choices=['add', 'sub', 'mul', 'div'], default='add')
parser.add_argument("-v", "--verbose", action="store_true", help="increase output verbosity")
opts = parser.parse_args()
logging.basicConfig(level=logging.INFO if opts.verbose else logging.WARNING)
log = logging.getLogger()
operation = getattr(operator, opts.operation)
log.info('Applying %s to %s', opts.operation, opts.number)
print(functools.reduce(operation, opts.number))

正确答案： D

4. 第 4 题：运行系统命令

知识点描述：在编写系统运维工具时，调用系统命令。

问题描述：编写 Linux 系统运维工具，调用系统命令查看 “/” 目录下文件，请从以下选项中选出你认为正确的选项：
A.

import shlex
import subprocess
def run(command):try:result = subprocess.getstatusoutput(command, shell=shlex.split(command), stderr=subprocess.STDOUT)return 0, resultexcept subprocess.CalledProcessError as e:return e.returncode, e.output
status, out = run('ls "/"')
print(status, out)

import shlex
import subprocess
def run(command):try:result = subprocess.check_output(command, shell=shlex.split(command), stderr=subprocess.STDOUT)return 0, resultexcept subprocess.CalledProcessError as e:return e.returncode, e.output
status, out = run('ls "/"')
print(status, out)

import gzip
text = 'text.txt'
with open(text, 'rt') as file:read_text = file.read()with gzip.open('compress.gz', 'wt', compresslevel = 9) as f:f.write(read_text)

import gzip
text = 'text.txt'
with open(text, 'rt') as file:read_text = file.read()with gzip.open('compress.gz', 'wt', compresslevel = 0) as f:f.write(read_text)

正确答案：B

5. 第 5 题：命令行中进度条显示

知识点描述：使用进度条显示当前任务完成进度。
问题描述：在执行耗时任务时，使用进度条显示已经完成了的任务进度，请从以下选项中选出你认为正确的选项：
A.

import shutil, sys
import time
def progressbar(func):def _func_with_progress(*args, **kwargs):max_width, _ = shutil.get_terminal_size()gen = func(*args, **kwargs)while True:try:progress = next(gen)except StopIteration as exc:sys.stdout.write('\n')return exc.valueelse:message = '[%s] {}%%'.format(progress)bar_width = max_width - len(message) + 3  filled = int(round(bar_width / 100.0 * progress))spaceleft = bar_width - filledbar = '=' * filled + ' ' * spaceleftsys.stdout.write((message+'\r') % bar)sys.stdout.flush()
@progressbar
def wait(seconds):start = time.time()step = seconds / 100.for i in range(1, 101):time.sleep(step)yield ireturn time.time() - start
if __name__ == '__main__':print("Waiting", wait(4))

import shutil, sys
import time
def progressbar(func):def _func_with_progress(*args, **kwargs):max_width, _ = shutil.get_terminal_size()gen = func(*args, **kwargs)while True:try:progress = next(gen)except StopIteration as exc:sys.stdout.write('\n')return exc.valueelse:message = '[%s] {}%%'.format(progress)bar_width = max_width - len(message) + 3  filled = int(round(bar_width / 100.0 * progress))spaceleft = bar_width - filledbar = '=' * filled + ' ' * spaceleftsys.stdout.write((message+'\r') % bar)sys.stdout.flush()return _func_with_progress
@progressbar
def wait(seconds):start = time.time()step = seconds / 100.for i in range(1, 101):time.sleep(step)return time.time() - start
if __name__ == '__main__':print("Waiting", wait(4))

import shutil, sys
import time
def progressbar(func):def _func_with_progress(*args, **kwargs):max_width, _ = shutil.get_terminal_size()gen = func(*args, **kwargs)while True:try:progress = next(gen)except StopIteration as exc:sys.stdout.write('\n')return exc.valueelse:message = '[%s] {}%%'.format(progress)bar_width = max_width - len(message) + 3  filled = int(round(bar_width / 100.0 * progress))spaceleft = bar_width - filledbar = '=' * filled + ' ' * spaceleftsys.stdout.write((message+'\r') % bar)sys.stdout.flush()return _func_with_progress
@progressbar
def wait(seconds):start = time.time()step = seconds / 100.for i in range(1, 101):time.sleep(step)yield ireturn time.time() - start
if __name__ == '__main__':print("Waiting", wait(4))

import shutil, sys
import time
def progressbar(func):def _func_with_progress(*args, **kwargs):max_width, _ = shutil.get_terminal_size()gen = func(*args, **kwargs)while True:try:progress = next(gen)except StopIteration as exc:sys.stdout.write('\n')return exc.valueelse:message = '[%s] {}%%'.format(progress)bar_width = max_width - len(message) + 3  filled = int(round(bar_width / 100.0 * progress))spaceleft = bar_width - filledbar = '=' * filled + ' ' * spaceleftsys.stdout.write((message+'\r') % bar)sys.stdout.flush()return _func_with_progress()
@progressbar
def wait(seconds):start = time.time()step = seconds / 100.for i in range(1, 101):time.sleep(step)yield ireturn time.time() - start
if __name__ == '__main__':print("Waiting", wait(4))

正确答案：C

试题代码地址

https://codechina.csdn.net/LOVEmy134611/python_problem