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