在Python中迭代一系列日期 [英] Iterating through a range of dates in Python

问题描述

我有以下代码来做到这一点，但我该怎么做得更好？现在我觉得它比嵌套循环要好，但是当你在一个列表解析中有一个生成器时，它开始得到Perl-one-linerish。

I have the following code to do this, but how can I do it better? Right now I think it's better than nested loops, but it starts to get Perl-one-linerish when you have a generator in a list comprehension.

day_count = (end_date - start_date).days + 1
for single_date in [d for d in (start_date + timedelta(n) for n in range(day_count)) if d <= end_date]:
    print strftime("%Y-%m-%d", single_date.timetuple())

笔记

• 我实际上并没有使用它来打印。这只是为了演示目的。


• $ code> start_date 和 end_date 变量是 datetime .date 对象，因为我不需要时间戳。 （他们将用于生成报告）。



Notes

• I'm not actually using this to print. That's just for demo purposes.
• The start_date and end_date variables are datetime.date objects because I don't need the timestamps. (They're going to be used to generate a report).

开始日期 2009-05-30 ，结束日期 2009-06-09 ：

For a start date of 2009-05-30 and an end date of 2009-06-09:

2009-05-30
2009-05-31
2009-06-01
2009-06-02
2009-06-03
2009-06-04
2009-06-05
2009-06-06
2009-06-07
2009-06-08
2009-06-09




推荐答案

为什么有两个嵌套迭代？对于我来说，它只产生一个相同的数据列表：

Why are there two nested iterations? For me it produces the same list of data with only one iteration:

for single_date in (start_date + timedelta(n) for n in range(day_count)):
    print ...

没有列表被存储，只有一个生成器被迭代。此外，生成器中的if似乎是不必要的。

And no list gets stored, only one generator is iterated over. Also the "if" in the generator seems to be unnecessary.

毕竟，线性序列只需要一个迭代器，而不是两个。

After all, a linear sequence should only require one iterator, not two.

也许最优雅的解决方案是使用生成器函数来完全隐藏/抽象范围的日期：

Maybe the most elegant solution is using a generator function to completely hide/abstract the iteration over the range of dates:

from datetime import timedelta, date

def daterange(start_date, end_date):
    for n in range(int ((end_date - start_date).days)):
        yield start_date + timedelta(n)

start_date = date(2013, 1, 1)
end_date = date(2015, 6, 2)
for single_date in daterange(start_date, end_date):
    print single_date.strftime("%Y-%m-%d")

注意：为了与内置 range（）的一致性（）这个迭代在到 end_date 之前停止的功能。所以对于包容性迭代，使用第二天，就像你在 range（）中一样。

NB: For consistency with the built-in range() function this iteration stops before reaching the end_date. So for inclusive iteration use the next day, as you would with range().

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