julian-date | 易学教程

Extract day of year and Julian day from a string date

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I have a string "2012.11.07" in python. I need to convert it to date object and then get an integer value of day of year and also Julian day . Is it possible? First, you can convert it to a datetime.datetime object like this: >>> import datetime >>> fmt = '%Y.%m.%d' >>> s = '2012.11.07' >>> dt = datetime.datetime.strptime(s, fmt) >>> dt datetime.datetime(2012, 11, 7, 0, 0) Then you can use the methods on datetime to get what you want… except that datetime doesn't have the function you want directly, so you need to convert to a time tuple >>> tt = dt.timetuple() >>> tt.tm_yday 312 The term

Convert a date vector into Julian day in R

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问题 I have a column of dates in the format: 16Jun10 and I would like to extract the Julian day. I have various years. I have tried the functions julian and mdy.date and it doesn\'t seem to work. 回答1: Try the following to convert from class character (i.e. text) to class POSIXlt , and then extract Julian day ( yday ): tmp <- as.POSIXlt("16Jun10", format = "%d%b%y") tmp$yday # [1] 166 For more details on function settings: ?POSIXlt ?DateTimeClasses Another option is to use a Date class, and then

Convert DateTime to Julian Date in C# (ToOADate Safe?)

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问题 I need to convert from a standard Gregorian date to a Julian day number. I\'ve seen nothing documented in C# to do this directly, but I have found many posts (while Googling) suggesting the use of ToOADate. The documentation on ToOADate does not suggest this as a valid conversion method for Julian dates. Can anyone clarify if this function will perform conversion accurately, or perhaps a more appropriate method to convert DateTime to a Julian formatted string. This provides me with the

Extract day of year and Julian day from a string date

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问题 I have a string \"2012.11.07\" in python. I need to convert it to date object and then get an integer value of day of year and also Julian day . Is it possible? 回答1: First, you can convert it to a datetime.datetime object like this: >>> import datetime >>> fmt = '%Y.%m.%d' >>> s = '2012.11.07' >>> dt = datetime.datetime.strptime(s, fmt) >>> dt datetime.datetime(2012, 11, 7, 0, 0) Then you can use the methods on datetime to get what you want… except that datetime doesn't have the function you