strptime

问题 Please what\'s wrong with my code: import datetime d = \"2013-W26\" r = datetime.datetime.strptime(d, \"%Y-W%W\") print(r) Display \"2013-01-01 00:00:00\", Thanks. 回答1: A week number is not enough to generate a date; you need a day of the week as well. Add a default: import datetime d = "2013-W26" r = datetime.datetime.strptime(d + '-1', "%Y-W%W-%w") print(r) The -1 and -%w pattern tells the parser to pick the Monday in that week. This outputs: 2013-07-01 00:00:00 %W uses Monday as the first

问题 Please consider the following $ R --vanilla > as.Date(\"01 Jan 2000\") Error in charToDate(x) : character string is not in a standard unambiguous format But that date clearly is in a standard unambiguous format. Why the error message? Worse, an ambiguous date is apparently accepted without warning or error and then read incorrectly! > as.Date(\"01/01/2000\") [1] \"0001-01-20\" I\'ve searched and found 28 other questions in the [R] tag containing this error message. All with solutions and

问题 I have some log files with times in the format HH:MM::SS.nano_seconds (e.g. 01:02:03.123456789). I would like to create a datetime in python so I can neatly do math on the time (e.g. take time differences). strptime works well for microseconds using %f. Do the Python datetime and time modules really not support nanoseconds? 回答1: You can see from the source that datetime objects don't support anything more fine than microseconds. As pointed out by Mike Pennington in the comments, this is

问题 When I try to parse a timestamp in the following format: \"Thu Nov 8 15:41:45 2012\", only NA is returned. I am using Mac OS X, R 2.15.2 and Rstudio 0.97.237. The language of my OS is Dutch: I presume this has something to do with it. When I try strptime , NA is returned: var <- \"Thu Nov 8 15:41:45 2012\" strptime(var, \"%a %b %d %H:%M:%S %Y\") # [1] NA Neither does as.POSIXct work: as.POSIXct(var, \"%a %b %d %H:%M:%S %Y\") # [1] NA I also tried as.Date on the string above but without %H:%M: