python 代码 strftime("%s") 错误

Question

python程序如下，报错：

文件“C:\Python\PyCharmProject\FaceBookCrawl\group_download.py”，第 31 行，在 getFeed 参数中 += "&since=" + SINCE.strftime("%s")
ValueError: Invalid format string

程序好像SINCE.strftime("%s")错了，怎么解决？

SINCE = datetime.datetime.now() - datetime.timedelta(DAYS)

params = "?fields=permalink_url,from,story,type,message,link,created_time,updated_time,likes.limit(0).summary(total_count),comments.limit(0).summary(total_count)"

#Default paging limit
params += "&amp&limit=" + DEFAULT_LIMIT

#Time-based limit
params += "&since=" + SINCE.strftime("%s")
graph_url = GRAPH_URL_PREFIX + group + "/feed" + params

Answer 1

其实应该是大写的S：

params += "&since=" + SINCE.strftime("%S")
                                           ^