---
title: Python模块timezone学习笔记
date: 2018-08-06 18:19:30
tags: [python]
categories: python
---
本文基于python3，记录了datetime包中的timezone用法。
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使用第三方扩展包pytz，构造指定时区。

> **astimezone**

`datetime.datetime.astimezone`是将原始输入解释为本地时区，然后再转换为目标时区，而pytz包的`localize`方法，是将原始输入直接解释为目标时区，例如：

```python
tz = pytz.timezone('Asia/Shanghai')
target_dt = datetime.datetime(2018, 8, 5, 0, 0, 0, 0)
print(repr(target_dt.astimezone(tz)))
print(repr(tz.localize(target_dt)))

# Output
# > datetime.datetime(2018, 8, 5, 8, 0, tzinfo=<DstTzInfo 'Asia/Shanghai' CST+8:00:00 STD>)
# > datetime.datetime(2018, 8, 5, 0, 0, tzinfo=<DstTzInfo 'Asia/Shanghai' CST+8:00:00 STD>)
```

> **timetuple**

由于`datetime.datetime.timetuple`方法不存储时区，所以如果需要构造不同时区的timestamp，需要使用`datetime.datetime.utctimetuple`方法。

```python
target_dt = datetime.datetime(2018, 8, 5, 0, 0, 0, 0)
print(repr(target_dt.utctimetuple()))
print(repr(target_dt.timetuple()))

# Output
# > time.struct_time(tm_year=2018, tm_mon=8, tm_mday=5, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=217, tm_isdst=0)
# > time.struct_time(tm_year=2018, tm_mon=8, tm_mday=5, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=217, tm_isdst=-1)
```

> `datetime.``timetuple`()[¶](https://docs.python.org/3/library/datetime.html#datetime.datetime.timetuple)
>
> Return a [`time.struct_time`](https://docs.python.org/3/library/time.html#time.struct_time) such as returned by [`time.localtime()`](https://docs.python.org/3/library/time.html#time.localtime). `d.timetuple()` is equivalent to `time.struct_time((d.year, d.month, d.day, d.hour, d.minute, d.second, d.weekday(), yday, dst))`, where `yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1` is the day number within the current year starting with `1` for January 1st. The `tm_isdst` flag of the result is set according to the [`dst()`](https://docs.python.org/3/library/datetime.html#datetime.datetime.dst) method: [`tzinfo`](https://docs.python.org/3/library/datetime.html#datetime.datetime.tzinfo) is `None` or [`dst()`](https://docs.python.org/3/library/datetime.html#datetime.datetime.dst) returns `None`, `tm_isdst` is set to `-1`; else if [`dst()`](https://docs.python.org/3/library/datetime.html#datetime.datetime.dst) returns a non-zero value, `tm_isdst`is set to `1`; else `tm_isdst` is set to `0`.

> `datetime.``utctimetuple`()[¶](https://docs.python.org/3/library/datetime.html#datetime.datetime.utctimetuple)
>
> If [`datetime`](https://docs.python.org/3/library/datetime.html#datetime.datetime) instance *d* is naive, this is the same as `d.timetuple()` except that `tm_isdst` is forced to 0 regardless of what `d.dst()` returns. DST is never in effect for a UTC time.
>
> If *d* is aware, *d* is normalized to UTC time, by subtracting `d.utcoffset()`, and a [`time.struct_time`](https://docs.python.org/3/library/time.html#time.struct_time) for the normalized time is returned. `tm_isdst` is forced to 0. Note that an [`OverflowError`](https://docs.python.org/3/library/exceptions.html#OverflowError) may be raised if *d*.year was`MINYEAR` or `MAXYEAR` and UTC adjustment spills over a year boundary.

目标需求，将东8区(+8)的`2018-08-05 00:00:00`转换为unix timestamp：

```python
tz = pytz.timezone('Asia/Shanghai')
target_dt = datetime.datetime(2018, 8, 5, 0, 0, 0, 0)
target_dt = tz.localize(target_dt)
print(time.mktime(target_dt.utctimetuple()))
print(target_dt.timestamp())

# Output
# > 1533398400.0
# > 1533398400.0
```

参考文档：

https://kkc.github.io/2015/07/08/dealing-with-datetime-and-timezone-in-python/