Python 时间戳 转换

timestamp-->date_str
    time:
        timestamp = time.time()     1629350338.4799922
        temp = time.localtime(timestamp)
        date_str = time.strftime('%Y-%m-%d %H:%M:%S', temp)     '2021-08-19 13:19:39'
    datetime:
        timestamp = datetime.datetime.now().timestamp()     1629350488.775833
        temp = datetime.datetime.fromtimestamp(timestamp)
        date_str = temp.strftime('%Y-%m-%d %H:%M:%S')   '2021-08-19 13:22:09'
date_str-->timestamp
    time:
        date_str = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime())
        temp = time.strptime(date_str, '%Y-%m-%d %H:%M:%S')
        timestamp = time.mktime(temp)
    datetime:
        date_str = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')
        temp = datetime.datetime.strptime(date_str, '%Y-%m-%d %H:%M:%S')
        timestamp = temp.timestamp()