计数器：一个简单的进度计数器

一个简单的进度计，用于打印for循环执行中的迭代次数和经过的时间。

> 从 mlxtend.utils 导入 Counter

概述

Counter类实现了一个用于显示for循环中迭代次数和经过时间的对象。请注意，Counter的实现是为了效率；因此，Counter仅提供非常基本的功能，以避免相对昂贵的评估（如if-else语句）。

参考文献

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示例 1 - 统计 for 循环中的迭代次数

from mlxtend.utils import Counter

import time

cnt = Counter()
for i in range(20):
    # 进行一些计算
    time.sleep(0.1)
    cnt.update()

20 iter | 2 sec

请注意，第一个数字显示当前迭代，而第二个数字显示在初始化Counter后经过的时间。

API

Counter(stderr=False, start_newline=True, precision=0, name=None)

Class to display the progress of for-loop iterators.

Parameters

• stderr : bool (default: True)

  Prints output to sys.stderr if True; uses sys.stdout otherwise.

• start_newline : bool (default: True)

  Prepends a new line to the counter, which prevents overwriting counters if multiple counters are printed in succession. precision: int (default: 0) Sets the number of decimal places when displaying the time elapsed in seconds.

• name : string (default: None)

  Prepends the specified name before the counter to allow distinguishing between multiple counters.

Attributes

• curr_iter : int

  The current iteration.

• start_time : float

  The system's time in seconds when the Counter was initialized.

• end_time : float

  The system's time in seconds when the Counter was last updated.

Examples

>>> cnt = Counter()
>>> for i in range(20):
...     # do some computation
...     time.sleep(0.1)
...     cnt.update()
20 iter | 2 sec
>>> print('The counter was initialized.'
' %d seconds ago.' % (time.time() - cnt.start_time))
The counter was initialized 2 seconds ago
>>> print('The counter was last updated'
' %d seconds ago.' % (time.time() - cnt.end_time))
The counter was last updated 0 seconds ago.

For more usage examples, please see https://rasbt.github.io/mlxtend/user_guide/utils/Counter/

Methods

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update()

Print current iteration and time elapsed.