Concatenating 2 vectors into 1 vector with the values adjacent to each other

2 vues (au cours des 30 derniers jours)
Hi, I have a three vectors: month, year, and partial pressure of carbon dioxide for 2914 observations. I am trying to use a program to analyze the seasonality of the data, but the program requires that the data be in a 2914x2 (2914 rows, 2 columns) matrix such that column one is the year and month (i.e. February 2012 would be 20121 and June 1985 would be 19856) and column 2 is the partial pressure of carbon dioxide. I've tried countless times to get the data in this format but no matter what I do when I concatenate it forms a 2914x3 matrix. Is there a way to actually concatenate the year and month vectors to get in the format "yearmonth" like 20121 or 19856? Thanks so much!
  3 commentaires
Moey Rojas
Moey Rojas le 30 Mai 2020
Most of my code has been a derivative of yearmonthCO2=[yr, mon, pCO2]. What I'm trying to do is get a [yearmonth, pCO2] output.

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Réponse acceptée

Star Strider
Star Strider le 30 Mai 2020
Modifié(e) : Star Strider le 30 Mai 2020
Yes. Use datetime to create them.
Example —
CO2_Mtx = [2012 01 rand; 2012 2 rand; 1985 5 rand; 1985 6 rand]; % Create Matrix
YM = datetime(num2str(CO2_Mtx(:,[1 2]),'%d %d'), 'InputFormat','yyyy MM', 'Format','yyyyMM'); % Convert ‘Years Month’ To ‘datetimeâ
CO2_Tbl = table(YM,CO2_Mtx(:,3), 'VariableNames',{'YearMth','CO2PP'}) % Table Of Results
That should work with the data as you have described it. Without your actual matrix however, I cannot be certain.
Producing —
CO2_Tbl =
4×2 table
YearMth CO2PP
_______ ________
201201 0.046171
201202 0.097132
198505 0.82346
198506 0.69483
EDIT —
Added ‘CO2_Tbl’ output.
  5 commentaires
Tommy
Tommy le 31 Mai 2020
I think this is a great answer and I hope you don't delete it. I'm not quite at the point where I think datetime when I ought to, but I'm getting there, thanks in part to this answer - that's one of the main reasons I spend time on this site! I'd suggest the OP accept this answer.
Star Strider
Star Strider le 31 Mai 2020
I decided to keep it posted!
The one glitch is that ‘PPCO2’ should have been ‘pCO2’. (And I was a Chemistry major!)
.

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Plus de réponses (2)

Bjorn Gustavsson
Bjorn Gustavsson le 30 Mai 2020
Why not simply do something like this:
Year_pressure = [year(:) + (month(:)-.5)/12,p_CO2(:)];
Here I've modified your conversion of year+month to "fractional years", mainly because I dont understand how you can map February 2012 to 20121 and June 1985 to 19856, but you can simply replace what I did for the dates with whatever you need for converting the year-month to the format you require.
HTH

Tommy
Tommy le 30 Mai 2020
Modifié(e) : Tommy le 30 Mai 2020
Should February 2012 map to 20122 rather than 20121? If so, maybe this will do the trick?
month = repmat((1:12)', 5, 1);
year = repelem((1998:2002)', 12, 1);
pCO2 = rand(60, 1);
data = [str2num(sprintf('%d%d\n',[year,month]')), pCO2];
(edit)
>> fprintf('%d %0.3f\n',data')
19981 0.132
19982 0.085
19983 0.232
19984 0.625
19985 0.372
19986 0.130
19987 0.679
19988 0.836
19989 0.662
199810 0.815
199811 0.924
199812 0.314
19991 0.499
...
  1 commentaire
Moey Rojas
Moey Rojas le 30 Mai 2020
Yes, It should have been 20122; that was a bad typo. That worked, thanks!

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