# How do I convert table data to double to manipulate them?

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Fernando De Ita le 2 Déc 2017
Modifié(e) : Stephen23 le 6 Juin 2024
I extract data from a table. When I retrieve an element, it is in table format, but I encounter an error when attempting to perform operations like multiplication. Is there a direct command or a series of steps to address this issue?
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Stephen23 le 25 Août 2021
Modifié(e) : Stephen23 le 25 Août 2021
"I extracted data from a table, when I get an element it comes as table format but when trying to make some operations like multiplication there is an error, is there any direct command or a series of steps?"
You could use TABLE2ARRAY, but by far the simplest and most efficient approach is to just use the correct indexing using curly braces to access the table content (not parentheses which returns another table, which is what you did).
The different types of indexing are clearly explained in the documentation:
Peter Perkins le 8 Nov 2021
This new example goes even further into indexing and the topic of "doing math on data stored in a MATLAB table":
It's a new-for-R2021b example, but doesn't require the latest MATLAB for anything (most anything?) it covers.

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### Réponse acceptée

Star Strider le 15 Mai 2024
Modifié(e) : MathWorks Support Team le 5 Juin 2024
There are several ways you can convert or extract table data to an array.
You can use dot notation or curly brace indexing, as described in the following documentation:
Access Data in Tables
https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-table.html
A = T.Variables% All table data concatenated into an array
A = T{:,:}% All table data concatenated into an array
A = T{rows,vars}% Specified rows and variables into an array
You can also use the "table2array" function.
A = table2array(T)
And finally, there are many operations you can perform on table data without converting it at all. For examples, see the following documentation:
Direct Calculations on Tables and Timetables
https://www.mathworks.com/help/matlab/matlab_prog/direct-calculations-on-tables-and-timetables.html
Calculations When Tables Have Both Numeric and Nonnumeric Data
https://www.mathworks.com/help/matlab/matlab_prog/calculations-when-tables-have-both-numeric-and-nonnumeric-data.html
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awesome
Peter Perkins le 28 Sep 2023
In recent versions of MATLAB, tables and timetables support many element+wise and reduction math operations:
t1 = table([1;2;3],[4;5;6]);
sum(t1,1)
ans = 1×2 table
Var1 Var2 ____ ____ 6 15
t2 = table([7;8;9],[10;11;12]);
t1 + t2
ans = 3×2 table
Var1 Var2 ____ ____ 8 14 10 16 12 18

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### Plus de réponses (3)

Peter Perkins le 19 Déc 2017
The answer might be as simple as something like T.Z = T.x .* T.y. Without more information, hard to tell.
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Roger Breton le 8 Mar 2021
Modifié(e) : Roger Breton le 8 Mar 2021
It does not work for me : all I want is to be able to import a range from Excel, and all I get is a "Table" on which I can't do any operation?
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Roger Breton le 9 Mar 2021
Thank you so much for extending your kind help, Peter.
Yes, all my data is numieric, doubles, in fact. It's just that I'm totally "green" with regards to MatLab data types. I think I used the table2array function to "convert" the data. Once converted, I was able to carry my "normal" arithmetic operation. I really have to give myself the time to learn Matlab...
Stephen23 le 25 Août 2021
Modifié(e) : Stephen23 le 6 Juin 2024
If you just need a numeric matrix, why are you importing the data as a table? Use READMATRIX instead.

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Arshey Dhangekar le 7 Juil 2021
Hello I have csv data of 18 columns and want to convert into double
so instead of writing 18 str2double code how can I convert all the 18 columns in short line of code
Temp.x310_Ambient__C_ = str2double (Temp.x310_Ambient__C_);
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Mohsin Munir le 25 Août 2021
I have data in excel. there are some coulmns having inputs. I want if i multiply two columns in matlab then the next column to be added in the same sheet rather than a new file in workspace. can anybody help me in this problem
Peter Perkins le 8 Nov 2021
1) Post a new question, don't ask a question in a reply to someone else's question.
2) This example may be of help for the topic of "doing math on data stored in a MATLAB table":
It's a new-for-R2021b example, but doesn't require the latest MATLAB for anything (most anything?) it covers.

Connectez-vous pour commenter.

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