[Python] 將 datetime 轉換成字串

>>> from datetime import datetime
>>> datetime.now()
datetime.datetime(2020, 3, 21, 22, 15, 12, 15172)

# 最簡單的方式就這樣做
>>> str(datetime.now())
'2020-03-21 22:15:22.177988'
>>> str(datetime.now())[-7:]
'.125355'
# 如果只要取到秒
>>> str(datetime.now())[:-7]
'2020-03-21 22:15:50'

# 使用 strftime 取到 micro-second
>>> datetime.now().strftime('%Y-%m-%d %H:%M:%S.%f')
'2020-03-21 22:16:27.581924'

# 使用 strftime 取到 milli-second
>>> datetime.now().strftime('%Y-%m-%d %H:%M:%S.%f')[:-3]
'2020-03-21 22:16:37.023'

參考資料：

• strftime() and strptime() Behavior