Is it possible to rename columns in a table?

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Chelsea
Chelsea 2015-2-18
评论： Jonathon Klepatzki 2023-10-16
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 个评论
Ruxandra Gabriela Ionescu
Ruxandra Gabriela Ionescu 2021-9-8
You all wrote the same thing, the same example. I asked a question and you answered with an example. I don't examples! I need the solution in my case.. It's simple...
It's unuseful this page, sorry...
per isakson
per isakson 2021-9-8
"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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采纳的回答

per isakson
per isakson 2022-4-28
编辑：MathWorks Support Team 2022-4-28
You can rename the variables in a table by using either the "Properties.VariableNames" property or the "renamevars" function. (In a table, the column-oriented arrays of data are called variables, not columns, because variables can have multiple columns of their own.)
For example, consider this small table with default variable names.
T = table((1:3)',(4:6)')
T =
  3×2 table
    Var1    Var2
    ____    ____
     1       4 
     2       5 
     3       6 
Rename the variables by using “Properties.VariablesNames”.
T.Properties.VariableNames = ["A","B"]
T =
  3×2 table
    A    B
    _    _
    1    4
    2    5
    3    6
Starting in R2020a, rename them by using “renamevars”.
T = table((1:3)',(4:6)');
T = renamevars(T,["Var1","Var2"],["Nums1","Nums2"])
T =
  3×2 table
    Nums1    Nums2
    _____    _____
      1        4 
      2        5 
      3        6 
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Silver
Silver 2018-10-28
Hello @per isakson ! I have an issue in here ! actually I have these columns names to generate to the table :
T.Properties.VariableNames = {'Date_Time' 'Latitude' 'Longitude' 'Course' 'Speed' 'Temp_SBE45' 'Cond_SBE45' 'SoundVel_SBE45' 'full' 'pH_SeaFET' 'Saturation' 'Salinity_SBE45' 'Temperature_Optode' 'flow_pCO2' 'pH_Meinsberg' 'Temp_in_SBE38' 'Temp_Meinsberg' 'Oxygen' 'pCO2' 'pressure' 'flow_in' 'flow_main' 'flow_pH' 'Turbidity' 'halffull' 'Chl_a' 'Variance' 'pH_Meinsberg' 'Variance' 'Temp_Meinsberg' 'Variance' 'pH_SeaFET' 'Variance' 'pCO2' 'Variance' 'pressure' 'Variance' 'flow_in' 'Variance' 'flow_main' 'Variance' 'flow_pH' 'Variance' 'flow_pCO2' 'Variance' 'halffull' 'Variance' 'full' 'Variance'}
But I always get an error message :
Duplicate variable name: 'Temperature_Optode'.
Any Ideas ?
per isakson
per isakson 2018-12-2
编辑：per isakson 2018-12-2
@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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更多回答（6 个）

Peter Perkins
Peter Perkins 2015-2-19
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
Campion Loong
Campion Loong 2021-10-20
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
Oleg Komarov
Oleg Komarov 2015-4-22
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 2017-7-21
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 个评论
Walter Roberson
Walter Roberson 2017-7-21
I disagree. t2 has only one column, which happens to be a 3 x 2 array.
... Any other interpretation would require that you be able to give separate column headers for each character in variable-length strings.
Peter Perkins
Peter Perkins 2017-7-21
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 个评论
per isakson
per isakson 2021-9-8
This is a new question and posting it as such increases the chances to get an answer.
Walter Roberson
Walter Roberson 2021-9-8
Ran in:
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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Sulaymon Eshkabilov
Ran in:
This way of an array to table conversion is also feasible and less computationally intensive.
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 = array2table(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

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