How to create this table/matrix?

Hi everyone

I need to create a matrix that is the concatenation of two different sources.

First column of concatenated matrix - First 10 entries of column SYMBOL of table CIV:

CIV =

  2448×3 table

    SYMBOL     TRADE_DATE    Price
    _______    __________    ____________________________

    {'SPX'}     7.393e+05               11.654           
    {'SPX'}     7.393e+05               11.337           
    {'SPX'}     7.393e+05               10.736           

Second column of concatenated matrix - All entries of ForecastDates:

T0 = datetime(2024,02,16);
T1 = datetime(busdate(T0,1));
T2 = datetime(busdate(T1,1));
T3 = datetime(busdate(T2,1));
T4 = datetime(busdate(T3,1));
T5 = datetime(busdate(T4,1));
T6 = datetime(busdate(T5,1));
T7 = datetime(busdate(T6,1));
T8 = datetime(busdate(T7,1));
T9 = datetime(busdate(T8,1));
T10 = datetime(busdate(T9,1));

ForecastDates = [T1 T2 T3 T4 T5 T6 T7 T8 T9 T10];

I need a 10 by 2 matrix. The first column is SYMBOL and second is ForecastDates'. I did the following but I am getting an error:

>> ForecastInfo = [CIV.SYMBOL(1:10,:) ForecastDates']
Error using horzcat
Inconsistent concatenation dimensions because a 10-by-1 'double' array was converted to a 1-by-1 'cell'
array. Consider creating arrays of the same type before concatenating.
 
>> CIV.SYMBOL(1:10,:)

ans =

  10×1 cell array

    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}
    {'SPX'}

>> ForecastDates'

ans =

      739302
      739303
      739304
      739305
      739308
      739309
      739310
      739311
      739312
      739315

>> 

Each is a 10 by 1 so it looks ok but I am not sure what I did wrong. Is someone able to help me with this?

Thank you

[Stephen23]

"Each is a 10 by 1 so it looks ok but I am not sure what I did wrong."

It is not meaningful to concatenate a cell array and a double array. Exactly as the error message tells you, you (should) convert them to the same data type before concatenating (e.g. NUM2CELL).

"I need a 10 by 2 matrix."

Sure, but of what class?

I suspect that you probably want TABLE() rather than concatenation.

[Manny]

@Stephen23, what do you mean by class?

I need columns 1 and 2 to be different data types b/c that is how the original CIV matrix is setup. How do I do this?

[Stephen23]

"what do you mean by class?"

Class is basically a fancy word for the type of an array (the terms type and class are often treated as synonyms).

MATLAB has several numeric class arrays, e.g. DOUBLE, SINGLE, UINT8, etc. Numeric arrays contain numbers.

MATLAB also has container classes (which are arrays that can contain other arrays), for example CELL, STRUCT, TABLE, etc.

https://www.mathworks.com/help/matlab/matlab_prog/fundamental-matlab-classes.html

An array itself is just the instance of one class.

"I need columns 1 and 2 to be different data types b/c that is how the original CIV matrix is setup. How do I do this?"

Use a TABLE:

https://www.mathworks.com/help/matlab/ref/table.html

Answer 1

[Walter Roberson]

ForecastInfo = table(CIV.SYMBOL(1:10,:), ForecastDates', 'VariableNames', {'Symbol', 'Forcecast Dates'});

[Manny]

thank you so much! it works