mean value for every one minute and time blanks between

Hi all!

I have a matrix with two columns: time(hours) & temperature. But I have time blank between the measurements. I want to find mean value of temperature for every one minute (0.0167 hours), but if it found a time difference ti+1-ti>0.08, it will start the next minute from the value after the blank. These are my data:

 12.353855  23.1
12.355585   24.5
12.357284   22.9
12.358982   23.8
12.360677   25.2
12.362379   22.5
12.364070   23.8
12.365759   24.2
12.367457   26.2
12.369162   25.9
12.370863   24.6
12.372571   26.7
12.374269   21.9
12.375964   24.8
12.377664   25.3 
12.379358   22.7
12.381062   21.5
12.382759   25.9
12.384461   24.3
12.386174   27.9
12.387877   22.8
12.389589   27.9
12.391289   28.1
12.392999   28.5
12.394866   28.4
12.396653   25.4
12.398355   24.6
12.400059   27.9
12.401765   25.9
12.403478   24.9
12.405176   24.6
12.406878   25.1
12.408587   26.9
12.410285   27.2
12.411974   28.4
12.413673   28.1
12.415377   28.5
12.417084   28.3
12.418792   27.9
12.420502   27.5
12.422201   23.5
12.423905   25.7
12.425616   26.9
12.427327   28.4
12.429039   21.6
12.430742   24.8
12.548259   27.2
12.549967   29.1
12.551696   28.5
12.553411   26.2
12.555119   25.3
12.556835   25.6
12.558541   24.9
12.560253   24.7
12.561979   25.8
12.563707   25.1
12.565423   25.2
12.567127   26.9
12.568838   26.3
12.570549   26.9
12.572253   25.9
12.573960   24.3
12.575676   22.9
12.577389   23.6
12.579099   21.9
12.580812   26.9
12.582526   25.3
12.584236   26.7
12.585938   28.1
12.587654   27.8
12.589361   26.9
12.591072   25.9
12.592776   23.2
12.594488   26.8
12.596212   27.2
12.597924   29.8
12.599636   30.5 
12.601343   33.8
12.603080   32.7
12.604791   31.9
12.606495   30.8
12.608208   29.7
12.609928   29.5
12.611652   28.8
12.613373   28.7
12.615088   28.5
12.616798   27.5
12.618511   25.9
12.620223   26.2
12.621948   25.9
12.623668   27.5
12.625381   28.3
12.627093   27.1
12.628804   26.2
12.746722   26.8
12.748493   27.9
12.750228   22.1
12.751951   27.9
12.753672   25.9
12.755397   24.6
12.757117   23.9
12.758842   22.8
12.760568   23.4
12.762300   24.1
12.764025   23.9
12.765754   23.6
12.767480   24.5
12.769198   24.7
12.770914   25.8
12.772649   26.7
12.774382   26.8
12.776115   25.2
12.777848   24.8
12.779577   25.2
12.781286   25.8

For example, after the value 46 there is a time blank, so i want the next minute will start from the value 47. Until the value 46 there are 5 minutes. 1:10, 11:20, 21:30, 31:40, 41:46 and then 47:56, 57:66, 67:76 and so on....

Any ideas??

Thank you!

Answer 1

[Peter Perkins]

There are a variety of ways to do this, all more or less involving creating a grouping variable that says what minute each row of your data are from. From there, you can use things like varfun (on a table), splitapply, or accumarray to compute the means in each group.

Since R2014b, you could use durations to represent the elapsed time.

In the recently-released R2016b, you can use timetables to do this in one line of code:

% given t and x as the two columns of data, make a timetable
>> tt = timetable(x,'RowTimes',t)
tt = 
       Time       x  
    _________    ____
    12.354 hr    23.1
    12.356 hr    24.5
    12.357 hr    22.9
    12.359 hr    23.8
    12.361 hr    25.2
[snip, 110 more rows]
>> tt.Time.Format = 'm'
tt = 
       Time        x  
    __________    ____
    741.23 min    23.1
    741.34 min    24.5
    741.44 min    22.9
    741.54 min    23.8
    741.64 min    25.2
[snip, 110 more rows]
>> ttm = retime(tt,'minutely','mean')
ttm = 
      Time       x   
    _______    ______
    741 min     23.75
    742 min     24.55
    743 min    26.433
    744 min     26.75
    745 min    26.067
    746 min       NaN
    747 min       NaN
[snip, 19 more rows]