How to search a specific row and a column from a csv file that are associated with the date that was selected?

How to search a specific row(s) and a column(s) from a csv file that is/are associated with the date that was selected and display which row(s) has this date.

I have 356 rows and the column #1 has data that start with 01/01/2022 up to 12/31/2022.

Now, if a user enter 01/27/2022 than I want to search for which row on the first column has a date that match the selected date once this row is found then I know column #2 has data for x-axis and column #3 has data for y-axis. So once I found this row(s) then I can plot the data that are on column #2 and #3 for the row(s) that was found.

The reason for me saying "rows" is because I have about 9000 rows of data and that I have over more than one row for each day!

Answer 1

[Arif Hoq]

try this. please follow the dateformat whenever user put the date. I have attached a random csv file.

data=readtable('VIX.csv','ReadVariableNames', false);
date=string(table2cell(data(:,1)));
DateFormat = '2014-05-26';
A=input('put the date: ');
[idx C]=ismember(A,date)
output= data(C,:);

[Steven Shaaya]

Hi,

Thank you for your help. I have tried date format such as 2015-12-16 , 2015/12/16 , or as it is on csv file 12/16/2015 but they all give me the same error! Would you please tell me what is going on?

I am getting the following error

Error using ismember (line 76)

First argument must be a string array, character vector, or cell array of character vectors.

[idx C]= ismember(A,date)

76 error(message('MATLAB:string:MustBeCharCellArrayOrString', firstInput));

[Steven Shaaya]

I do not think the issue is from the date format as I made a new column with a basic input such as 1,2,5,4,8,22,12,3,6,7,9,1,.....

But it is still given me the same error. I am using Matlab 2019b.

[Steven Shaaya]

Thank you, I found the issue. I had to enter my input as "12/16/2015" that is with quotation marks!

[Arif Hoq]

nice.. i think you got your solution, right ?

[Steven Shaaya]

Yes, but I am geting another problem now! I can not plot the data for selected rows and columns.

I get this error

" Error using tabular/plot

Too many input arguments."

I looked into the same problem online but they are not working for me.

Here is how I am trying to plot them.

%%%%%

data=readtable('Cooling.csv','ReadVariableNames', true)

date=string(table2cell(data(:,6)))

IN=input('put the date: ');

[idx C]= ismember(IN,date)

Data_Selected= data(C:(C+4),:)

x=Data_Selected(:,5)

y=Data_Selected(:,3)

plot(x,y)

%%%%

I know how to use readmatrix and hard code the specified rows and columns to plot them which it does work, but readmatrix does not work with the solution that you provide to me.

Also, I do not want to hard coded because the numbers of rows can be 1 or as large as 10000!

please note that on "Data_Selected= data(C:(C+4),:)"

for C+4 I am just trying to say plot from Row C to Row C+4 just for the purpose to see how does it work.

Can you help on this?

Answer 2

[Peter Perkins]

It's a LOT easier using a timetable:

>> x = (1:20)';
>> y = rand(size(x));
>> date = datetime(2022,1,repelem(1:4,5)');
>> tt = timetable(date,x,y)
tt =
  20×2 timetable
       date        x        y    
    ___________    __    ________
    01-Jan-2022     1    0.072686
    01-Jan-2022     2     0.63163
    01-Jan-2022     3     0.88471
    01-Jan-2022     4     0.27271
    01-Jan-2022     5     0.43641
[snip]
    04-Jan-2022    16     0.90465
    04-Jan-2022    17     0.50452
    04-Jan-2022    18     0.51629
    04-Jan-2022    19     0.31903
    04-Jan-2022    20     0.98664
>> tt("2022-01-03",:)
ans =
  5×2 timetable
       date        x        y    
    ___________    __    ________
    03-Jan-2022    11     0.46445
    03-Jan-2022    12     0.94098
    03-Jan-2022    13    0.050084
    03-Jan-2022    14     0.76151
    03-Jan-2022    15      0.7702
>> plot(tt.x('2022-01-03'),tt.y('2022-01-03'))

If you are doing this a lot, look at using rowfun with date as the grouping variable.

You are getting your data from a file. If your version of MATLAB is too old to have readtimetable, use readtable and table2timetable.