Is it possible to rename columns in a table?

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Chelsea
Chelsea on 18 Feb 2015
Answered: Campion Loong on 20 Oct 2021
Hi,
I'm hoping there's a simple way to rename columns in a table. I don't need anything complicated, I'd just like to rename, for example, the 2nd, 7th, and 16th columns of a table - inside a function.
Thanks!
  2 Comments
per isakson
per isakson on 8 Sep 2021
"I don't examples! I need the solution in my case.. It's simple... It's unuseful this page, sorry..."
No it's not simple to understand what meaning you put in the word solution.
OP has accepted an answer, thus I believe OP found it at least marginally useful.

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Accepted Answer

per isakson
per isakson on 18 Feb 2015
Example
%%Create a table
T = table(['M';'M';'F';'F';'F'],[38;43;38;40;49],...
[71;69;64;67;64],[176;163;131;133;119])
T =
Var1 Var2 Var3 Var4
____ ____ ____ ____
M 38 71 176
M 43 69 163
F 38 64 131
F 40 67 133
F 49 64 119
%%Modify variable names
T.Properties.VariableNames = {'Gender' 'Age' 'Height' 'Weight'}
T =
Gender Age Height Weight
______ ___ ______ ______
M 38 71 176
M 43 69 163
F 38 64 131
F 40 67 133
F 49 64 119
  6 Comments
per isakson
per isakson on 2 Dec 2018
@Silver, this is a new question rather than a comment. Posting it as such increases the chances to get an answer.
There are many duplicates in that row. Obviously, duplicates are not allowed (although it's not clearly stated in the documentation(?)). However, 'Temperature_Optode' is not a duplicate.

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More Answers (6)

Peter Perkins
Peter Perkins on 19 Feb 2015
The following are also possible:
Rename only some variables (note the parentheses on the left-hand side and the cell array of strings on the right-hand side) ...
>> T.Properties.VariableNames([1 3]) = {'Gender' 'Height'}
T =
Gender Var2 Height Var4
______ ____ ______ ____
M 38 71 176
M 43 69 163
F 38 64 131
F 40 67 133
F 49 64 119
... or rename only one variable (note the braces on the LHS instead of parentheses, and the raw string on the RHS) ...
>> T.Properties.VariableNames{2} = 'Age'
T =
Gender Age Height Var4
______ ___ ______ ____
M 38 71 176
M 43 69 163
F 38 64 131
F 40 67 133
F 49 64 119
... or rename a variable when you only know its (old) name.
>> T.Properties.VariableNames{'Var4'} = 'Weight'
T =
Gender Age Height Weight
______ ___ ______ ______
M 38 71 176
M 43 69 163
F 38 64 131
F 40 67 133
F 49 64 119
  2 Comments
Cbhihe
Cbhihe on 22 Jun 2017
Actually you are renaming variables here, not column (headers) as requested in OP. Is there a way to just rename headers and not the actual variable names ?

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Oleg Komarov
Oleg Komarov on 22 Apr 2015
My tableutils() has renameVarNames() that does exactly that with added flexibility.
The description is usually updated on https://github.com/okomarov/tableutils

Martin Patz
Martin Patz on 21 Jul 2017
I agree with Cbhihe's comment above, the proposed solutions do not directly answer the OP's question. I face a case where the differentiation between column header variable is indeed important. For instance
v1 = [1:3]';
v2 = [2:4]';
m = [v1, v2];
t1 = table(v1, v2)
t2 = table(m)
gives two different results:
t1 =
v1 v2
__ __
1 2
2 3
3 4
t2 =
m
______
1 2
2 3
3 4
with previously posted answers it is not possible to rename the columns of t2 by specifying 'VariableNames', {'column_1', 'column_2'} as additional arguments to the table command. However you can split up a matrix into separate columns, which are then configureable, using the array2table command.
Example:
t3 = array2table(m, 'VariableNames', {'column_1', 'column_2'})
column_1 column_2
________ ________
1 2
2 3
3 4
  2 Comments
Peter Perkins
Peter Perkins on 21 Jul 2017
This is the very reason why we try to refer to the vertical things in a table as "variables", not as "columns".
Martin, m in your example is an Nx2 double. Double arrays have no way to "name" their columns, and you are correct that just putting an Nx2 double into a table does not add that capability. You might do one of two things:
1) As you say, it's pretty easy to split the Nx2 into two Nx1 column vectors. But presumably, there's some reason why you'd want m as an Nx2 rather than splitting it.
2) You could make m itself a table with two variables, and out that in a table. That would be kind of pointless if the outer table only had m as its one variable, but in cases wher you have a table with several variables, one of which has multiple columns, it can be useful. Currently, the display for a "table in a table" is not very helpful, but all of the subscripting and so on works as you'd expect. On the other hand, a table is not a double, so while this strategy keeps those two columns "together" in some sense, you might want to work with m as a double.

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Ruxandra Gabriela Ionescu
I have matrix B=[10 11 12 13 14; 15 16 17 18 19; 20 21 22 23 24; 25 26 27 28 29; 30 31 32 33 34].
  1. How can I set the name of the columns with ab, bc, cd, de and ef?
  2. How can I add a new column "fg" with the value 100?
  3. How can I set the values from cd and lines 1,2,3 at NaN value? I don't know what is NaN.
Thank you!
  2 Comments
Walter Roberson
Walter Roberson on 8 Sep 2021
Sounds like homework to me,
B=[10 11 12 13 14; 15 16 17 18 19; 20 21 22 23 24; 25 26 27 28 29; 30 31 32 33 34]
B = 5×5
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
T = cell2table(num2cell(B), 'VariableNames', {'ab', 'bc', 'cd', 'de', 'ef'})
T = 5×5 table
ab bc cd de ef __ __ __ __ __ 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
T.fg(1:5) = sum(T{3,:}) - T.ab(1)
T = 5×6 table
ab bc cd de ef fg __ __ __ __ __ ___ 10 11 12 13 14 100 15 16 17 18 19 100 20 21 22 23 24 100 25 26 27 28 29 100 30 31 32 33 34 100
T.cd(1:3) = inf - inf
T = 5×6 table
ab bc cd de ef fg __ __ ___ __ __ ___ 10 11 NaN 13 14 100 15 16 NaN 18 19 100 20 21 NaN 23 24 100 25 26 27 28 29 100 30 31 32 33 34 100

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Campion Loong
Campion Loong on 20 Oct 2021
Renaming table and timetable variables has become straightforward since R2020a:
renamevars Rename variables in table or timetable
Also check out the suite of convenient functions for table/timetable manipulations
addvars Add variables to table or timetable
removevars Delete variables from table or timetable
mergevars Combine table or timetable variables into multicolumn variable
movevars Move variables in table or timetable
splitvars Split multicolumn variables in table or timetable
convertvars Convert table or timetable variables to specified data type

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