help needed in map reduce code.

Question

naadiya khudabux 2016-10-14

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/307286-help-needed-in-map-reduce-code

评论： naadiya khudabux 2016-10-14

hello .. i am trying to convert the UTC to GMT data format with MapReduce on desktop platform.i want to convert the time into datetime format.like this

2016-25-07 01:26:40    
2016-25-07 01:26:40    
2016-25-07 01:26:40    
2016-25-07 01:26:40    
2016-25-07 01:26:40    
2016-25-07 04:13:20    
2016-25-07 04:13:20    
2016-25-07 04:13:20    
2016-25-07 01:26:40    
2016-25-07 01:26:40    
2016-25-07 01:26:40    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00    
2016-25-07 07:00:00

i am getting wrong results from my code. can someone help me

   >> read(outds)
   ans = 
     Key            Value       
    ______    __________________
    'date'    [18598x1 datetime]
  end
function Map(data, info, intermKVStore)
  %datetime = data.RequestTime(~isnan(data.RequestTime));
  dateformated=datetime(data.RequestTime/1000,'ConvertFrom','posixTime',...
    'TimeZone','Asia/Hong_Kong','Format','dd-MMM-yyyy HH:mm:ss.SSS')
     add(intermKVStore, 'datetime', dateformated);
  end
function reduce(intermKey, intermValIter, outKVStore)
    date = 0;
    while hasnext(intermValIter)
        date = date + getnext(intermValIter);
    end
add(outKVStore,'date',date);
end

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Answer 1

Guillaume 2016-10-14

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https://ww2.mathworks.cn/matlabcentral/answers/307286-help-needed-in-map-reduce-code#answer_238954

在 MATLAB Online 中打开

If your input is in UTC and you want the datetime objects to display time in your local timezone, you first need to construct the datetime object in UTC timezone then switch to your local one:

   dateformated=datetime(data.RequestTime/1000,'ConvertFrom','posixTime',...
    'TimeZone','UTC','Format','dd-MMM-yyyy HH:mm:ss.SSS');  %read data as Posix UTC
   dateformated.Timezone = ''Asia/Hong_Kong'; %switch to new timezone. dateformated is adjusted accordingly