python3 datetime模块

from datetime import datetime


'''datetime时间模块'''
# 拿到当前计算机的系统时间 年-月-日 时:分:秒.毫秒
print(datetime.now())
print(type(datetime.now()))

2019-11-25 23:25:46.941824
<class 'datetime.datetime'>

from datetime import datetime

# 获取当前系统时间
now = datetime.strftime(datetime.now(), "%Y-%m-%d %H:%M:%S")
print(now)
print(type(now))

2019-11-27 21:40:30
<class 'str'>

from datetime import datetime

# 格林尼治时间，和我们相差8小时,utc协调世界时 Coordinated Universal Time
# coordinated 协调的
# universal 通用的
d1 = datetime.utcnow()
print(d1)

2019-11-22 13:27:33.084041

from datetime import datetime

# 用指定的时间创建datetime
print(datetime(2019, 11, 22, 12, 13, 14))
print(type(datetime(2019, 11, 22, 12, 13, 14)))

2019-11-22 12:13:14
<class 'datetime.datetime'>

from datetime import datetime

# 计算时间差
d1 = datetime(2019, 11, 22, 12, 13, 14)
d2 = datetime(2019, 11, 23, 14, 43, 14)
diff = d2 - d1
# seconds只计算当天的时分秒差（单位秒）
print(diff.seconds)
# total_seconds()计算年月日时分秒差（单位秒）
print(diff.total_seconds())

9000
95400.0

from datetime import datetime

# 计算时间差
d1 = datetime(2019, 11, 22, 12, 22 , 22)
d2 = datetime(2019, 11, 21, 12, 22, 22)
diff = d1 - d2
print(diff.seconds)  # 单纯从时分秒来计算
print(diff.total_seconds())  # 包括年月日计算

0
86400.0

from datetime import datetime


def get_diff_datetime(d1, d2):
    '''计算两个格式化时间之间差了多少年月日时分秒'''
    diff = d2 - d1
    year, days = divmod(diff.days, 365)
    month, day = divmod(days, 30)
    seconds = diff.seconds
    hour, seconds2 = divmod(seconds, 3600)
    minute, second = divmod(seconds2, 60)
    return year, month, day, hour, minute, second

date1 = datetime(2018, 1, 2, 12, 30, 10)
date2 = datetime(2019, 6, 12, 18, 40, 20)
year, month, day, hour, minute, second = get_diff_datetime(date1, date2)
print(f"两个格式化时间之间差了{year}年{month}月{day}日{hour}时{minute}分{second}秒")

两个格式化时间之间差了1年5月11日6时10分10秒

from datetime import datetime

# 时间格式化strftime， format格式化
d = datetime(2019, 11, 22, 12, 13, 14)
print(d.strftime("%Y-%m-%d %H:%M:%S"))
print(type(d.strftime("%Y-%m-%d %H:%M:%S")))

print(d.strftime("%Y/%m/%d %H:%M:%S"))
print(type(d.strftime("%Y/%m/%d %H:%M:%S")))

2019-11-22 12:13:14
<class 'str'>
2019/11/22 12:13:14
<class 'str'>

from datetime import datetime

# 字符串转化为时间格式strptime, parse转化
d = "2019-11-22 12:13:14"
print(datetime.strptime(d, "%Y-%m-%d %H:%M:%S"))
print(type(datetime.strptime(d, "%Y-%m-%d %H:%M:%S")))

2019-11-22 12:13:14
<class 'datetime.datetime'>

from datetime import datetime

'''格式必须一致，不然会报错'''

# 字符串转化为日期时间格式
s = "2018-4-6 12:34:18"
print(datetime.strptime(s, "%Y/%m/%d %H:%M:%S"))

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-2-d9390be238e2> in <module>()
      5 # 字符串转化为日期时间格式
      6 s = "2018-4-6 12:34:18"
----> 7 print(datetime.strptime(s, "%Y/%m/%d %H:%M:%S"))

~Anaconda3lib\_strptime.py in _strptime_datetime(cls, data_string, format)
    563     """Return a class cls instance based on the input string and the
    564     format string."""
--> 565     tt, fraction = _strptime(data_string, format)
    566     tzname, gmtoff = tt[-2:]
    567     args = tt[:6] + (fraction,)

~Anaconda3lib\_strptime.py in _strptime(data_string, format)
    360     if not found:
    361         raise ValueError("time data %r does not match format %r" %
--> 362                          (data_string, format))
    363     if len(data_string) != found.end():
    364         raise ValueError("unconverted data remains: %s" %

ValueError: time data '2018-4-6 12:34:18' does not match format '%Y/%m/%d %H:%M:%S'