Change string date/time to be understandable for mathematica

Question

I'm trying to convert a string of a data and time to be understandable for mathematica (I want to make time related plots).

However, I can get my head around how to do this.

For example:

temp = "Sun Jun 01 22:00:21 +0000 2014";

I have tried the following commands (and many more variations):

DateList[{temp, {"DayName", "Month", "Day", "Hour", "Minute", 
   "Second", "TimeZone", "Year"}}];
DateList[{temp, {"DayName", "Month", "Day", "Hour", ":", "Minute", 
   ":", "Second", "TimeZone", "Year"}}]

Both gave me this type of error:

DateString::str: "String \!\(\"Sun Jun 01 22:00:21 +0000 2014\"\) cannot be interpreted as a date in format {\!\(\"DayName\", \"Month\", \"Day\", \"Hour\", \"Minute\", \"Second\", \"TimeZone\", \"Year\"\)}."

Can anyone tell what I'm doing wrong? Thank you!!

Answer 1

The problem is with "TimeZone", that its not defined, and with using "Month" instead of "MonthName".

This works:

DateList[{"Sun Jun 01 22:00:21 2014", {"DayName", "MonthName", "Day", "Hour", "Minute", "Second", "Year"}}]

Are the strings in temp with fixed format? Then removing the characters will do

DateList[{StringDrop[temp, {21, 26}], {"DayName", "MonthName", "Day", "Hour", "Minute", "Second", "Year"}}]

Otherwise

DateList[ToString@ImportString[temp, "Table"][[1, {6, 2, 3, 4}]]]

I'm sure somebody else can work some magic to make this shorter and more efficient.

Answer 2

Some options

Your date

date = "Sun Jun 01 22:00:21 +0000 2014"; 

Eliminate wrong entry

rep = StringReplace[date, "+0000" -> ""]

"Sun Jun 01 22:00:21 2014"

Convert to List

list = rep // DateList

{2014, 6, 1, 22, 0, 21.}

Find day

day = DayName[list]

Sunday

Consolidate

{day}~Join~list

{Sunday, 2014, 6, 1, 22, 0, 21.}

Convert to DateObject @ GMT

obj = DateObject[list, TimeZone -> 0]

Convert to your local time

tzc = TimeZoneConvert[obj, $TimeZone] 

Transform to DateList

tzc // DateList

{2014, 6, 2, 0, 0, 21.}

Convert to another CalendarType

DateObject[list, CalendarType -> "Jewish"]

Answer 3

Manually fixing the timezone.

datecalc[t_] := Module[{},

  t2 = StringSplit[t, " " | ":"];
  tzsign = StringTake[t2[[7]], 1]; 
  tzhrs = ToExpression[StringTake[t2[[7]], {2, 3}]]; 
  tzmin = ToExpression[StringTake[t2[[7]], -2]];
  {hour, min} = ToExpression[t2[[{4, 5}]]];

  If[SameQ[tzsign, "+"],
   h2 = hour + tzhrs; m2 = min + tzmin,
   h2 = hour - tzhrs; m2 = min - tzmin];

  ymd = Take[DateList[{StringJoin[
        Riffle[Append[Take[t2, {2, 3}], Last@t2], " "]],
       {"MonthName", "Day", "Year"}}], 3];

  DateList[Join[ymd, {h2, m2}, {ToExpression[t2[[6]]]}]]]

Works for UTC-02:30

datecalc["Sun Jun 01 22:00:21 -0230 2014"]

{2014, 6, 1, 19, 30, 21.}

and UTC+13:45

datecalc["Fri Dec 31 11:00:21 +1345 1999"]

{2000, 1, 1, 0, 45, 21.}

Answer 4

At first I tried this hack:

ClearAll;
temp = "Sun Jun 01 22:00:21 +0000 2014";
td = If[StringFreeQ[temp, "-"],  
   DateList[{temp, {"DayNameShort", " ", "MonthNameShort", " ", 
      "Day", " ", "Hour24", ":", "Minute", ":", "Second", " +", 
      "Millisecond", " ", "Year"}}], 
   DateList[{temp, {"DayNameShort", " ", "MonthNameShort", " ", 
      "Day", " ", "Hour24", ":", "Minute", ":", "Second", " -", 
      "Millisecond", " ", "Year"}}]
   ];
tx = If[StringFreeQ[temp, "-"], 
  DateList[td, 
   TimeZone -> Plus[(FractionalPart[Last[td]]* 100), $TimeZone] ],
      DateList[td, 
       TimeZone -> Plus[(-FractionalPart[Last[td]]* 100), $TimeZone]]]
(* {2014, 6, 1, 22, 0, 21.} *)

Since there is no "TimeZone" pattern match expression, I hacked the "Millisecond". However, millisecond is limited to 3 digits, so we get round off errors.

Next I tried this:

ClearAll;
temp = "Sun Jun 01 22:00:21 +0000 2014";
DateList[{StringDrop[
   StringRotateRight[StringInsert[temp, " ", -1], 5], -7], {"Year", 
   " ", "DayNameShort", " ", "MonthNameShort", " ", "Day", " ", 
   "Hour24", ":", "Minute", ":", "Second"}}, 
 TimeZone -> 
  Plus[(ToExpression[
     StringJoin[
      StringTrim[
       StringTake[
        StringRotateRight[StringInsert[temp, " ", -1], 
         5], {-7, -4}]], 
      StringTrim[
       ToString[
        N[Rationalize[
          ToExpression[
            StringTrim[
             StringTake[
              StringRotateRight[StringInsert[temp, " ", -1], 
               5], {-3, -1}]]]/60]]], "0"]
      ]]), $TimeZone]]
(* {2014, 6, 1, 22, 0, 21.} *)

Add space to end, rotate the string, and adjust the date pattern expression. If you put this as a Module function would have more freedom to reduce rotations. Still not certain about the TimeZone stuff.