How to Add Headings to a list of data

Here is the code I have.

function[root,ea,iter]=secant(func,delta,xr,es,maxit,varargin)
if nargin<3,error('atleast 3 input arguments required'),end
if nargin<4|isempty(es),es=0.0001;end
if nargin<5|isempty(maxit),maxit=50;end
iter=0;
T=[]
while (1)
    xrold=xr;
    xr=xr-((delta*xr*func(xr))/(func(xr+(delta*xr))-func(xr)));
    iter=iter+1;
    if xr~=0, ea=abs((xr-xrold)/xr)*100;end
    if ea<=es|iter>=maxit,break,end
  funcxr=func(xr); 
  T=[T;[iter,xr,func(xr),ea]];
end
T

root=xr;

Here is the output.

>> secant(@(x) 6*x^2-13*x-5,10^-6,1.2)

T =

     []


T =

    1.0000    9.7428  437.8779   87.6832
    2.0000    5.5290  106.5398   76.2143
    3.0000    3.5319   23.9303   56.5448
    4.0000    2.7174    3.9799   29.9710
    5.0000    2.5145    0.2472    8.0718
    6.0000    2.5001    0.0012    0.5757
    7.0000    2.5000    0.0000    0.0029


ans =

    2.5000

I need to have headings on the top of the colmuns and have no clue how to add them. Please help

Answer 1

[Star Strider]

If you have R2013b or later, use a table. The documentation explains how to specify and add the variable names. Note that if you have R2019b or later, the variable names do not need to be valid MATLAB identifiers.

[Emily]

I have attempted to use table and I do not undestand how to get the information from all iterations into a single table.

[Star Strider]

With your current code and arguments, this array2table call:

Tout = array2table(T, 'VariableNames',{'iter','xr','func(xr)','ea'})

produces this reault:

Tout =

  7×4 table

    iter      xr       func(xr)        ea    
    ____    ______    __________    _________

     1      9.7428        437.88       87.683
     2       5.529        106.54       76.214
     3      3.5319         23.93       56.545
     4      2.7174        3.9799       29.971
     5      2.5145       0.24716       8.0718
     6      2.5001      0.001243      0.57567
     7         2.5    3.3171e-08    0.0029246

There are a number of different ways to create tables.

Make appropriate changes to get the result you want.

Answer 2

[Jon]

In general, MATLAB doesn't provide for column or row labels for matrices.

You could put the array into a MATLAB table and label the columns (variable names) there.

Here is a simple example where I turn a 5 by 3 array into a table and label the columns

A = rand(5,3)
Atbl = array2table(A,'VariableNames',{'cat','dog','tortoise'})

You should be able to adapt this to your situation.

For more info on working with tables see https://www.mathworks.com/help/matlab/matlab_prog/create-a-table.html

[Emily]

I have attempted to use table and I do not undestand how to get the information from all iterations into a single table.

[Jon]

First get it all into an array (matrix) as you are doing already. Then when you have all of the data in the array (after your while loop) use the array2table command as I earlier suggested.

[Jon]

p.s. It looks like StarStrider and I collided on providing you with similar answers at around the same time. I hadn't seen his posted yet when I sent mine.