Combine multiple columns into a single column keeping the column names?

Dear all,

I have a matrix with dimensions 24*366. Each row corresponds to a time in the day (hour 1 to hour 24) and each column to a year's day (01-Jan-2020 to 31-Dec-2020). How do I convert the multiple columns to a single column? Also, I want to create a new column with the date that each cell corresponds to. I have seen in the forum that to transform multiple columns into one I can do:

A=[ 1 2 3 4
    5 6 7 8
    9 1 2 3]  
out=A(:)

or

out=reshape(A,[],1)

However, the date ID column is essential, and I don't know how to get it. I have attached a picture of a simple example of what I want.

Thank you in advance!

[Stephen23]

The simplest approach is to use https://www.mathworks.com/help/matlab/ref/table.stack.html

[Angelavtc]

@Stephen Thank you very much, this should work. But to use this, when I call my file from excel, it does not import the column headers. How do I get Matlab to import them and have them in date format?

[the cyclist]

What command are you using to import your data from Excel? I would suggest readtable.

[Angelavtc]

@the cyclist you are right... I did this:

t = readtable('Spot2020.xlsx', 'ReadVariableNames', true);

However the column names are copy in this format 'x01_Jan_2020', How can I change them to a datetime format?

Thank you!

[the cyclist]

As will have been mentioned in a warning message, readtable appended the 'x' at the beginning to the column headers, so that they would valid names for MATLAB variables.

I think that probably the most intuitive way to deal with that is to choose the input argument prevents that from happening:

readtable(...,'VariableNamingRule','preserve')

and then convert using datetime:

dt = datetime('01_Jan_2020','InputFormat','dd_MMM_yyyy')

dt = datetime
   01-Jan-2020

That being said, I'm not sure that this is the best start-to-finish solution to achieve the final result you want (doing the pivot, etc.). People might be able to think about this a bit more holistically, if you post your Excel file (or a small, representative sample) here to test solutions.

[Angelavtc]

@the cyclist Thank you, it worked! I wrote the following code:

t = readtable('Spot2020.xlsx','PreserveVariableNames',true);

I am sorry for not showing the excel file before. I am attaching an small example. However, I have the solution. Thank you, again!