Re: split a number to Date format

*To*: mathgroup at smc.vnet.net*Subject*: [mg124275] Re: split a number to Date format*From*: "Hans Michel" <hmichel at cox.net>*Date*: Sun, 15 Jan 2012 04:51:08 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201201140754.CAA01282@smc.vnet.net>

Derek: filterTS[dt_String] := Module[{y, m, d, h, mi, s}, {y, m, d, h, mi, s} = Map[FromDigits, Partition[IntegerDigits[ToExpression[dt]], 2]]; y = y + 2000; DateList[{y, m, d, h, mi, s}] ] In[2]:= filterTS["111205020000"] Out[2]= {2011, 12, 5, 2, 0, 0.} Took advantage of the fact that the string format can be grouped by 2. Hans -----Original Message----- From: Hans Michel [mailto:hmichel at cox.net] Sent: Saturday, January 14, 2012 11:01 AM To: 'Derek Martin'; 'mathgroup at smc.vnet.net' Subject: [mg124275] Re: split a number to Date format The nice thing about Regular Expression is that it has been around a while now and there is a good place to go find tried, tested and sometimes well documented pattern matching strings. I was very pleased when WRI introduced Regular Expression in Mathematica. Even with Mathematica's (in their words "powerful") pattern matching, I learned Regular Expressions some 6-7 years before Mathematica came out. So I feel more comfortable around Regular Expressions. As far as I know, I don't see an equivalent publically available library of Mathematica pattern matching. So I found a Regular Expression on this site http://regexlib.com/REDetails.aspx?regexp_id=2641 This pattern match will match ISO 8601 date time format with or without the delimiters. Try StringCases["111205020000", RegularExpression[ "(\\d{2}|\\d{4})(?:\\-)?([0]{1}\\d{1}|[1]{1}[0-2]{1})(?:\\-)?([0-2]\ {1}\\d{1}|[3]{1}[0-1]{1})(?:\\s)?([0-1]{1}\\d{1}|[2]{1}[0-3]{1})(?::)?\ ([0-5]{1}\\d{1})(?::)?([0-5]{1}\\d{1})"] -> "20$1,$2,$3,$4,$5,$6"] or d = "111205020000"; dl= StringCases[d,RegularExpression["(\\d{2}|\\d{4})(?:\\-)?([0]{1}\\d{1}|[1]{1} [0-2]{1})(?:\\-)?([0-2]{1}\\d{1}|[3]{1}[0-1]{1})(?:\\s)?([0-1]{1}\\d{1}|[2]{ 1}[0-3]{1})(?::)?([0-5]{1}\\d{1})(?::)?([0-5]{1}\\d{1})"]-> "20$1,$2,$3,$4,$5,$6"]; dl You may also translate the RE pattern matching to the faster Mathematica String matching. I don't know how RE is implemented in Mathematica but I would think it is probably slower than the older built in matching techniques. Also note that a 2 digit year poses a problem of what to use when the 2 digits is greater than current year. When do you use "19" or "20" to designate century? The result is a list but it needs further processing to get to a DateList. You asked for help. This is what I could do with the time I had. I will come back to it for a complete solution if time permits. Hans -----Original Message----- From: Derek Martin [mailto:cdmartin at me.com] Sent: Saturday, January 14, 2012 1:54 AM To: mathgroup at smc.vnet.net Subject: [mg124275] split a number to Date format I have experimental data in spreadsheet format. The first column is a time stamp in the format 111205020000. If I could parse or split the number 111205020000 into {11,12,05,02,00,00} and replace the first 11 with 2011, the Date commands would work fine. I can do the replacing, but am having difficulty seeing how to split the number into {11,12,05,02,00,00}. DateString[{2011, 12, 05, 02, 00, 00}] gives "Mon 5 Dec 2011 02:00:00" Any help to convert my number to the right Date format would be appreciated. I am using Mathematica 8. Thanks in Advance Derek

**References**:**split a number to Date format***From:*Derek Martin <cdmartin@me.com>