python timestamp和datetime之间转换详解

# '2015-08-28 16:43:37.283' --> 1440751417.283 
# 或者 '2015-08-28 16:43:37' --> 1440751417.0 
def string2timestamp(strValue): 
 
  try:     
    d = datetime.datetime.strptime(strValue, "%Y-%m-%d %H:%M:%S.%f") 
    t = d.timetuple() 
    timeStamp = int(time.mktime(t)) 
    timeStamp = float(str(timeStamp) + str("%06d" % d.microsecond))/1000000 
    print timeStamp 
    return timeStamp 
  except ValueError as e: 
    print e 
    d = datetime.datetime.strptime(str2, "%Y-%m-%d %H:%M:%S") 
    t = d.timetuple() 
    timeStamp = int(time.mktime(t)) 
    timeStamp = float(str(timeStamp) + str("%06d" % d.microsecond))/1000000 
    print timeStamp 
    return timeStamp 

# 1440751417.283 --> '2015-08-28 16:43:37.283' 
def timestamp2string(timeStamp): 
  try: 
    d = datetime.datetime.fromtimestamp(timeStamp) 
    str1 = d.strftime("%Y-%m-%d %H:%M:%S.%f") 
    # 2015-08-28 16:43:37.283000' 
    return str1 
  except Exception as e: 
    print e 
    return ''