我有一个Python命令行程序,需要一段时间才能完成。我想知道完成跑步所需的确切时间。

我看过timeit模块,但它似乎只适用于小代码片段。我想给整个节目计时。


当前回答

对于使用Jupyter笔记本的数据人员

在单元格中,可以使用Jupyter的%%time魔术命令来测量执行时间:

%%time
[ x**2 for x in range(10000)]

输出

CPU times: user 4.54 ms, sys: 0 ns, total: 4.54 ms
Wall time: 4.12 ms

这将仅捕获特定单元的执行时间。如果您想捕获整个笔记本(即程序)的执行时间,可以在同一目录中创建一个新笔记本,并在新笔记本中执行所有单元格:

假设上面的笔记本名为example_notebook.ipynb。在同一目录中的新笔记本中:

# Convert your notebook to a .py script:
!jupyter nbconvert --to script example_notebook.ipynb

# Run the example_notebook with -t flag for time
%run -t example_notebook

输出

IPython CPU timings (estimated):
  User   :       0.00 s.
  System :       0.00 s.
Wall time:       0.00 s.

其他回答

这是获取程序运行时间的最简单方法:

在程序末尾编写以下代码。

import time
print(time.clock())

对于使用Jupyter笔记本的数据人员

在单元格中,可以使用Jupyter的%%time魔术命令来测量执行时间:

%%time
[ x**2 for x in range(10000)]

输出

CPU times: user 4.54 ms, sys: 0 ns, total: 4.54 ms
Wall time: 4.12 ms

这将仅捕获特定单元的执行时间。如果您想捕获整个笔记本(即程序)的执行时间,可以在同一目录中创建一个新笔记本,并在新笔记本中执行所有单元格:

假设上面的笔记本名为example_notebook.ipynb。在同一目录中的新笔记本中:

# Convert your notebook to a .py script:
!jupyter nbconvert --to script example_notebook.ipynb

# Run the example_notebook with -t flag for time
%run -t example_notebook

输出

IPython CPU timings (estimated):
  User   :       0.00 s.
  System :       0.00 s.
Wall time:       0.00 s.
from time import time
start_time = time()
...
end_time = time()
time_taken = end_time - start_time # time_taken is in seconds
hours, rest = divmod(time_taken,3600)
minutes, seconds = divmod(rest, 60)

我也喜欢Paul McGuire的回答,并提出了一个更符合我需求的上下文管理器表单。

import datetime as dt
import timeit

class TimingManager(object):
    """Context Manager used with the statement 'with' to time some execution.

    Example:

    with TimingManager() as t:
       # Code to time
    """

    clock = timeit.default_timer

    def __enter__(self):
        """
        """
        self.start = self.clock()
        self.log('\n=> Start Timing: {}')

        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        """
        """
        self.endlog()

        return False

    def log(self, s, elapsed=None):
        """Log current time and elapsed time if present.
        :param s: Text to display, use '{}' to format the text with
            the current time.
        :param elapsed: Elapsed time to display. Dafault: None, no display.
        """
        print s.format(self._secondsToStr(self.clock()))

        if(elapsed is not None):
            print 'Elapsed time: {}\n'.format(elapsed)

    def endlog(self):
        """Log time for the end of execution with elapsed time.
        """
        self.log('=> End Timing: {}', self.now())

    def now(self):
        """Return current elapsed time as hh:mm:ss string.
        :return: String.
        """
        return str(dt.timedelta(seconds = self.clock() - self.start))

    def _secondsToStr(self, sec):
        """Convert timestamp to h:mm:ss string.
        :param sec: Timestamp.
        """
        return str(dt.datetime.fromtimestamp(sec))

使用line_profiler。

line_profiler将描述单个代码行执行所需的时间。分析器通过Cython在C语言中实现,以减少分析开销。

from line_profiler import LineProfiler
import random

def do_stuff(numbers):
    s = sum(numbers)
    l = [numbers[i]/43 for i in range(len(numbers))]
    m = ['hello'+str(numbers[i]) for i in range(len(numbers))]

numbers = [random.randint(1,100) for i in range(1000)]
lp = LineProfiler()
lp_wrapper = lp(do_stuff)
lp_wrapper(numbers)
lp.print_stats()

结果将是:

Timer unit: 1e-06 s

Total time: 0.000649 s
File: <ipython-input-2-2e060b054fea>
Function: do_stuff at line 4

Line #      Hits         Time  Per Hit   % Time  Line Contents
==============================================================
     4                                           def do_stuff(numbers):
     5         1           10     10.0      1.5      s = sum(numbers)
     6         1          186    186.0     28.7      l = [numbers[i]/43 for i in range(len(numbers))]
     7         1          453    453.0     69.8      m = ['hello'+str(numbers[i]) for i in range(len(numbers))]