Problem in special characters

Dear all;

I have a ready code contain this command within a function

---------------------------------------------------

        [pvdata,~]=xlsread([Newfolder, Mono70W999]);

when i lunch it an error appear ( tha path and the file names are correct)

Unrecognized function or variable 'Newfolder'.

Error in PVModuleCurveFitting/Open (line 85)

[pvdata,~]=xlsread([Newfolder, Mono70W999])

Error while evaluating UIControl Callback.

• I uhave problem understaning the use of square brackets in xlsread because i used to work with these syntax

num = xlsread(filename)

num = xlsread(filename,sheet)

num = xlsread(filename,xlRange)

num = xlsread(filename,sheet,xlRange)

num = xlsread(filename,sheet,xlRange,'basic')

[num,txt,raw] = xlsread(___)

• also i want to know the purpose of using ~ alone ?

Answer 1

[Voss]

1. The error, "Unrecognized function or variable 'Newfolder'." means that the variable 'Newfolder' is not defined in the function that's calling xlsread, at the time xlsread is called.

2. The square brackets construct a file name by horizontally concatenating the variables 'Newfolder' and 'Mono70W999'. Example:

Newfolder = 'C:\Data';
Mono70W999 = 'Project1.xlsx';
result = [Newfolder, Mono70W999]

result = 'C:\DataProject1.xlsx'

Then that file name is passed to xlsread as the only input, so this is using the "num = xlsread(filename)" syntax.

Note that fullfile is better than square brackets for constructing file paths because it inserts directory separators between its arguments as needed. Example:

result = fullfile(Newfolder, Mono70W999)

result = 'C:\Data/Project1.xlsx'

[MATLAB Answers runs on a Linux platform,which uses slash ( / ) so that's why that's there. If you run it in Windows you'd get a backslash ( \ ) instead.]

3. The purpose of ~ is to indicate that the second output from xlsread is discarded. In this case, the ~ is unnecessary because the first output of xlsread is the same regardless of how many outputs are requested, so you'd get the same behavior with out = xlsread(filename) syntax.

Some other function besides xlsread might output different things depending on how many outputs are requested, in which case the [out1,~] = func(in) syntax might be necessary.

[YASSER]

Thank you fo your answer

i tried literally what you said

still facing a problem with different error due to my misunderstanding of () and []

here is my modification

function Open(~,~)
        Newfolder= 'C:\Users\HA\Desktop\PV Parameter estimation\CurveFittingTools\Newfolder';
        Mono70W999 = 'Project1.xlsx';
        [filename, pathname] = uigetfile('*.csv');
        if isequal(filename,0)  % Handling Cancel button pressed
            return;
        end
        pvdata = xlsread[Newfolder, Project1];
        set(hPmax,'String',num2str(pvdata(6,2)));

And here is the error

Error: File: PVModuleCurveFitting.m Line: 87 Column: 25

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

[Voss]

Presuming that you want to read the file that was selected:

function Open(~,~)
      [filename, pathname] = uigetfile('*.csv');
      if isequal(filename,0)  % Handling Cancel button pressed
          return;
      end
      pvdata = xlsread(fullfile(pathname,filename));

Although readmatrix or readtable is recommended over xlsread.

[YASSER]

Dear sir; as you see in attached photo

I always get an ampty [] from pvdata which mean that am not loading the csv file as i am encircling in workspace and command windows.

[Stephen23]

Please upload the CSV file Mono70W999.csv by clicking the paperclip button.

As Voss already recommended, you should use READTABLE or READMATRIX instead of XLSREAD.

Note that CSV files are not Excel files, they are text files. XLSREAD is the wrong tool.

[Voss]

@YASSER: The file you have circled, Mono70W999.csv, appears to be located in 'C:\Users\HA\Desktop\PV Parameter estimation\CurveFittingTools', which makes its full path as follows:

'C:\Users\HA\Desktop\PV Parameter estimation\CurveFittingTools\Mono70W999.csv'

but you are trying to read

'C:\Users\HA\Desktop\PV Parameter estimation\CurveFittingTools\Newfolder\Mono70W999.csv'

Do you see the difference?

Also, why are you bothering to call uigetfile if you're not going to use its output?

I wrote:

pvdata = xlsread(fullfile(pathname,filename));

And you are doing:

pvdata = xlsread(fullfile(Newfolder,Mono70W999));

Do you want to read whatever file the user selected via uigetfile? If that's the case, use what I wrote and remove the variables Newfolder and Mono70W999.

Or do you want to always read the same Mono70W999.csv file, regardless of what file was selected with uigetfile? If that's the case, use what you wrote and remove the call to uigetfile.

[YASSER]

1-The file is located both paths: the one that you see and the second is in the new folder , so this is not an issue

2-i am calling uigetfile because am going to change parameter to estimate others

So am gonna use it's output later

3- Do you want to read whatever file the user selected via uigetfile? my answer is yes, and yes i used both (what u wrote and also my variables) alwyas got emty []

My only issue is that i want to load this csv data by using only xlsread, and not readtable or others

[Voss]

Please do as Stephen suggested and upload the file using the paperclip button.

[YASSER]

i have to upload using Xlsread Because there a bunch of steps to foillow depending on this step

Concern the type csv ,I can change it to xlsx and i know the disavantages of doing it

But i have to read using Xlsread

And i always get an empty []

[Voss]

Please upload the file to this forum by clicking the paperclip button in the Insert section of the toolbar above where you type a comment.

(Paperclip button to upload a file to the Answers forum, circled in green.)

[Steven Lord]

Without seeing the actual file I think it's going to be impossible or nearly impossible to offer any suggestions for how to resolve the problem where you receive an [] as the output from xlsread. Just based on what we know already, I'm guessing the CSV file is empty. Seeing the actual file is the only way to confirm or refute my guess. So please attach the file to a comment as Stephen23 and Voss have requested using the button above the editor where you type your comment.

[YASSER]

Sorry to be late

The file is not empty

I used it as CSV and xlsx without result

I have upload both csv and code

I appretiate your Help

[Voss]

pathname = '.';
filename = 'Mono70W9999.csv';

readtable can read the file properly:

readtable(fullfile(pathname,filename),'NumHeaderLines',15,'VariableNamingRule','preserve','VariableNamesLine',15)

ans = 151x3 table
    V (V)    I (A)    P (W) 
    _____    _____    ______

       0         5         0
    0.13     4.999    0.6757
    0.27     4.997     1.351
     0.4     4.996    2.0259
    0.54     4.994    2.7004
    0.67     4.993    3.3746
    0.81     4.992    4.0483
    0.94      4.99    4.7217
    1.08     4.989    5.3947
    1.21     4.987    6.0672
    1.35     4.986    6.7394
    1.48     4.984    7.4112
    1.62     4.983    8.0826
    1.75     4.981    8.7536
    1.89      4.98    9.4243
    2.02     4.979    10.095

However, from your code I gather that you need the parameter values in the header as well, in which case it is convenient to use readmatrix instead:

pvdata = readmatrix(fullfile(pathname,filename))

pvdata = 166x3

NaN 9.0000 NaN NaN NaN NaN NaN NaN NaN NaN 20.2700 NaN NaN 5.0000 NaN NaN 69.5253 NaN NaN 15.4800 NaN NaN 4.4910 NaN NaN 3.5760 NaN NaN 0.6850 NaN

disp(pvdata(4:14,2)) % parameters

   20.2700
    5.0000
   69.5253
   15.4800
    4.4910
    3.5760
    0.6850
   41.9000
  999.0000
   36.0000
    0.6378

disp(pvdata(16:end,:)) % data

         0    5.0000         0
    0.1300    4.9990    0.6757
    0.2700    4.9970    1.3510
    0.4000    4.9960    2.0259
    0.5400    4.9940    2.7004
    0.6700    4.9930    3.3746
    0.8100    4.9920    4.0483
    0.9400    4.9900    4.7217
    1.0800    4.9890    5.3947
    1.2100    4.9870    6.0672
    1.3500    4.9860    6.7394
    1.4800    4.9840    7.4112
    1.6200    4.9830    8.0826
    1.7500    4.9810    8.7536
    1.8900    4.9800    9.4243
    2.0200    4.9790   10.0945
    2.1600    4.9770   10.7643
    2.2900    4.9760   11.4338
    2.4300    4.9740   12.1028
    2.5600    4.9730   12.7715
    2.7000    4.9710   13.4397
    2.8300    4.9700   14.1076
    2.9700    4.9680   14.7751
    3.1000    4.9670   15.4422
    3.2400    4.9650   16.1082
    3.3700    4.9640   16.7737
    3.5100    4.9620   17.4388
    3.6400    4.9600   18.1010
    3.7800    4.9560   18.7595
    3.9100    4.9540   19.4190
    4.0500    4.9520   20.0795
    4.1800    4.9490   20.7395
    4.3200    4.9470   21.4005
    4.4600    4.9460   22.0616
    4.5900    4.9440   22.7222
    4.7300    4.9420   23.3825
    4.8600    4.9410   24.0438
    5.0000    4.9400   24.7048
    5.1300    4.9380   25.3654
    5.2700    4.9370   26.0256
    5.4000    4.9360   26.6862
    5.5400    4.9350   27.3478
    5.6700    4.9340   28.0091
    5.8100    4.9330   28.6702
    5.9400    4.9320   29.3310
    6.0800    4.9310   29.9915
    6.2100    4.9300   30.6517
    6.3500    4.9290   31.3126
    6.4800    4.9280   31.9735
    6.6200    4.9270   32.6341
    6.7500    4.9260   33.2945
    6.8900    4.9250   33.9547
    7.0200    4.9250   34.6147
    7.1600    4.9240   35.2745
    7.2900    4.9230   35.9340
    7.4300    4.9220   36.5930
    7.5600    4.9210   37.2517
    7.7000    4.9200   37.9102
    7.8300    4.9190   38.5684
    7.9700    4.9190   39.2263
    8.1000    4.9180   39.8841
    8.2400    4.9170   40.5415
    8.3700    4.9160   41.1988
    8.5100    4.9150   41.8552
    8.6500    4.9140   42.5111
    8.7800    4.9130   43.1668
    8.9200    4.9120   43.8222
    9.0500    4.9110   44.4774
    9.1900    4.9100   45.1323
    9.3200    4.9090   45.7869
    9.4600    4.9080   46.4405
    9.5900    4.9070   47.0933
    9.7300    4.9060   47.7458
    9.8600    4.9050   48.3981
   10.0000    4.9040   49.0500
   10.1300    4.9020   49.7016
   10.2700    4.9010   50.3524
   10.4000    4.9000   51.0007
   10.5400    4.8990   51.6487
   10.6700    4.8970   52.2963
   10.8100    4.8960   52.9435
   10.9400    4.8950   53.5904
   11.0800    4.8930   54.2344
   11.2100    4.8910   54.8775
   11.3500    4.8900   55.5202
   11.4800    4.8880   56.1625
   11.6200    4.8860   56.8016
   11.7500    4.8840   57.4314
   11.8900    4.8810   58.0604
   12.0200    4.8780   58.6862
   12.1600    4.8750   59.3068
   12.2900    4.8720   59.9264
   12.4300    4.8680   60.5323
   12.5600    4.8630   61.1352
   12.7000    4.8580   61.7301
   12.8400    4.8530   62.3186
   12.9700    4.8470   62.8993
   13.1100    4.8410   63.4719
   13.2400    4.8330   64.0265
   13.3800    4.8230   64.5487
   13.5100    4.8130   65.0616
   13.6500    4.8010   65.5490
   13.7800    4.7890   66.0307
   13.9200    4.7780   66.5169
   14.0500    4.7620   66.9433
   14.1900    4.7480   67.3856
   14.3200    4.7280   67.7500
   14.4600    4.7080   68.0906
   14.5900    4.6880   68.4358
   14.7300    4.6660   68.7463
   14.8600    4.6400   68.9859
   15.0000    4.6140   69.2234
   15.1300    4.5810   69.3483
   15.2700    4.5460   69.4439
   15.4000    4.5110   69.5079
   15.5400    4.4630   69.3841
   15.6700    4.4210   69.3184
   15.8100    4.3810   69.2837
   15.9400    4.3280   69.0406
   16.0800    4.2650   68.6034
   16.2100    4.2080   68.2526
   16.3500    4.1350   67.6258
   16.4800    4.0560   66.8945
   16.6200    4.0050   66.5871
   16.7500    3.9230   65.7553
   16.8900    3.8500   65.0488
   17.0300    3.7540   63.9358
   17.1600    3.6640   62.9049
   17.3000    3.5760   61.8706
   17.4300    3.4620   60.3629
   17.5700    3.3010   58.0125
   17.7000    3.2300   57.1998
   17.8400    3.1280   55.8244
   17.9700    2.9890   53.7427
   18.1100    2.8360   51.3760
   18.2400    2.6960   49.2024
   18.3800    2.5500   46.8830
   18.5100    2.3950   44.3570
   18.6500    2.2390   41.7765
   18.7800    2.0680   38.8652
   18.9200    1.9140   36.2186
   19.0500    1.7460   33.2803
   19.1900    1.5720   30.1824
   19.3200    1.4170   27.3951
   19.4600    1.2510   24.3510
   19.5900    1.0440   20.4681
   19.7300    0.8750   17.2709
   19.8600    0.6240   12.4091
   20.0000    0.4350    8.7141
   20.1300    0.2000    4.0301
   20.2700         0         0

plot(pvdata(16:end,1),pvdata(16:end,2))

xlsread generates an error with this file (it does not return an empty array):

xlsread(fullfile(pathname,filename))

Error using xlsread
Unable to read XLS file /users/mss.system.pcgmv/Mono70W9999.csv. File is not in recognized format.

[YASSER]

Thank you Mr Voss

Thank you all of you

[Voss]

You're welcome!