the for loop is only giving me the last value

Question

Othman Alkandri 2022-1-19

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1631545-the-for-loop-is-only-giving-me-the-last-value

评论： Star Strider 2022-1-19

20170401damlbmp_zone.csv

Hello guys, the for loop only gives me the last value of the .csv file. Some people have the same issue as mine seam. Most posts recommend adding a zero vector. I added the zero vector, but the problem is still remaining.

Data_table = readtable('20170401damlbmp_zone.csv')
Data_20170401 = readmatrix('20170401damlbmp_zone.csv')
% take the N.Y.K and North inromation from the loaded files
North_20170401 = zeros(360,6);
N_Y_K_20170401 = zeros(360,6);
for i = 10 :15 : 360
    %for j = 1:1:24
        disp( Data_20170401(i,3))
        N_Y_K_20170401(i,1)=  Data_20170401(i,3);
        x= i+1;
        North_20170401(i,1) = Data_20170401(x,3);
  %  end
end 

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the cyclist 2022-1-19

Can you upload the data, using the paperclip icon in the INSERT section of the toolbar?

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Answer 1

Star Strider 2022-1-19

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https://ww2.mathworks.cn/matlabcentral/answers/1631545-the-for-loop-is-only-giving-me-the-last-value#answer_877075

在 MATLAB Online 中打开

There are likely a lot of zeros in the vectors because of the way ‘i’ is defined.

The loop is likely not necessary anyway.

Try something like this —

i = 10 : 15 : 360;
N_Y_K_20170401 =  Data_20170401(i,3);
North_20170401 = Data_20170401(i+1,3);

.

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Star Strider 2022-1-19

在 MATLAB Online 中打开

The ‘Time Stamp’ variable is a bit ambiguous and needs clarification, however my code works with this file, producing 2 (24x1) vectors (with a slight change in the subscripting, using curly braces {} instead of parentheses () to return a double array instead of a table) —

Data_20170401 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/867505/20170401damlbmp_zone.csv', 'VariableNamingRule','preserve')
Warning: The DATETIME data was created using format 'MM/dd/uuuu HH:mm' but also matched 'dd/MM/uuuu HH:mm'.
To avoid ambiguity, supply a datetime format using SETVAROPTS, e.g. 
  opts = setvaropts(opts,varname,'InputFormat','MM/dd/uuuu HH:mm');
Data_20170401 = 360×6 table
Time StampNamePTIDLBMP ($/MWHr)Marginal Cost Losses ($/MWHr)Marginal Cost Congestion ($/MWHr)__________________________________________________________________________________________________________

    04/01/2017 00:00    {'CAPITL'}    61757        42.86                     0.49                             -31.81              
    04/01/2017 00:00    {'CENTRL'}    61754        12.27                     0.14                              -1.56              
    04/01/2017 00:00    {'DUNWOD'}    61760        34.44                     0.98                              -22.9              
    04/01/2017 00:00    {'GENESE'}    61753        11.68                    -0.08                              -1.19              
    04/01/2017 00:00    {'H Q'   }    61844        10.26                    -0.31                                  0              
    04/01/2017 00:00    {'HUD VL'}    61758        33.04                     0.88                              -21.6              
    04/01/2017 00:00    {'LONGIL'}    61762         34.9                     1.44                              -22.9              
    04/01/2017 00:00    {'MHK VL'}    61756        13.07                     0.15                              -2.36              
    04/01/2017 00:00    {'MILLWD'}    61759        34.57                     0.97                             -23.03              
    04/01/2017 00:00    {'N.Y.C.'}    61761        34.48                     1.09                             -22.83              
    04/01/2017 00:00    {'NORTH' }    61755        10.15                    -0.41                                  0              
    04/01/2017 00:00    {'NPX'   }    61845        38.27                     0.75                             -26.95              
    04/01/2017 00:00    {'O H'   }    61846        12.04                     -0.1                              -1.57              
    04/01/2017 00:00    {'PJM'   }    61847        21.21                     0.37                             -10.28              
    04/01/2017 00:00    {'WEST'  }    61752        12.24                     0.15                              -1.53              
    04/01/2017 01:00    {'CAPITL'}    61757        39.35                      0.5                             -28.28              
i = 10 : 15 : 360;
N_Y_K_20170401 =  Data_20170401{i,3}
N_Y_K_20170401 = 24×1
       61761
       61761
       61761
       61761
       61761
       61761
       61761
       61761
       61761
       61761
North_20170401 = Data_20170401{i+1,3}
North_20170401 = 24×1
       61755
       61755
       61755
       61755
       61755
       61755
       61755
       61755
       61755
       61755
PTIDu = unique(Data_20170401{:,3});                         % Information: Inique Values
idx61755 = find(Data_20170401{:,3} == 61755)                % Information: Find Indices
idx61755 = 24×1
    11
    26
    41
    56
    71
    86
   101
   116
   131
   146
D61755 = diff(idx61755)                                     % Information: Find Intervals
D61755 = 23×1
    15
    15
    15
    15
    15
    15
    15
    15
    15
    15
idx61761 = find(Data_20170401{:,3} == 61761)                % Information: Find Indices
idx61761 = 24×1
    10
    25
    40
    55
    70
    85
   100
   115
   130
   145
D61761 = diff(idx61761)                                     % Information: Find Intervals
D61761 = 23×1
    15
    15
    15
    15
    15
    15
    15
    15
    15
    15

Further investigation reveals that the ‘PTID’ values repeat periodically (every 15 indices) so the same number always presents in the vectors.

So the loop is not necesary.

Has the problem been solved?

.

Othman Alkandri 2022-1-19

@Star Strider

Thank you a lot

Star Strider 2022-1-19

As always, my pleasure!

.

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