How can I copy a column I already have and add it on to the end of my matrix?

I have some data with time followed by various parameters (see example below)

All I want to do is take the 3rd column (4th if you include the time) and create a new column at the end with the same data

2018-01-01T01:00  53.000   0.000 268.450  -1.000   0.100 157.000
2018-01-01T02:00  53.000   0.000 267.750  -1.000   0.200  51.000
2018-01-01T03:00  53.000   0.000 268.450  -1.000   0.100 142.000
2018-01-01T04:00  53.000   0.000 269.550  -1.000   0.200  14.000

I would really appreciate some help with this!

Thanks

[Jan]

Is this a text file, an excel file, a table oject or a string?

[William Campbell]

txt

Answer 1

[madhan ravi]

EDITED

https://www.mathworks.com/help/matlab/ref/addvars.html - as you already have it as a table like shown in your previous question.

Example:

T=readtable('sample.txt'); % your rawdata filename 
T.Var1=datetime(T.Var1,'Format','yyyy-MM-dd''T''mm:ss')
New=addvars(T,T{:,4},'After',size(T,2))

Gives:

New =

  4×8 table

          Var1          Var2    Var3     Var4     Var5    Var6    Var7     Var8 
    ________________    ____    ____    ______    ____    ____    ____    ______

    2018-01-01T01:00     53      0      268.45     -1     0.1     157     268.45
    2018-01-01T02:00     53      0      267.75     -1     0.2      51     267.75
    2018-01-01T03:00     53      0      268.45     -1     0.1     142     268.45
    2018-01-01T04:00     53      0      269.55     -1     0.2      14     269.55

Download the attached file to experiment.

[William Campbell]

I don't want it as a table and it's a different data set, is there no way matlab will recognise it as just a text file?

[madhan ravi]

Since your data contains datetime it's possible to have them as a table like shown above or as cells like show below:

T=readtable('sample.txt','ReadVariableNames',0); % your rawdata filename 
T.Var1=datetime(T.Var1,'Format','yyyy-MM-dd''T''mm:ss')
N=table2cell(T);
S=size(T);
New=cell(S(1),S(end)+1);
New(:,1:end-1)=N;
New(:,end)=N(:,4)

Gives:

New =

  4×8 cell array

  Columns 1 through 5

    {[2018-01-01T01:00]}    {[53]}    {[0]}    {[268.4500]}    {[-1]}
    {[2018-01-01T02:00]}    {[53]}    {[0]}    {[267.7500]}    {[-1]}
    {[2018-01-01T03:00]}    {[53]}    {[0]}    {[268.4500]}    {[-1]}
    {[2018-01-01T04:00]}    {[53]}    {[0]}    {[269.5500]}    {[-1]}

  Columns 6 through 8

    {[0.1000]}    {[157]}    {[268.4500]}
    {[0.2000]}    {[ 51]}    {[267.7500]}
    {[0.1000]}    {[142]}    {[268.4500]}
    {[0.2000]}    {[ 14]}    {[269.5500]}

[William Campbell]

Thanks Madhan

I've got it as a table as I want it, how would i delete a variable from a table then ? and add one full of 0's?

[madhan ravi]

Anytime :) , if you got the answer to your original question("How can I copy a column I already have and add it on to the end of my matrix?") make sure to accept the answer.

"I've got it as a table as I want it, how would i delete a variable from a table then ? and add one full of 0's?"

% example
T.Var3=zeros(size(T,1),1) % this replaces the 3rd variable with zeros

[William Campbell]

I would like to make a new column at the end with zeros?

[madhan ravi]

T{:,end}=0 % replaces last column
T=addvars(T,zeros(size(T,1),1),'After',size(T,2)) % appends last column with zeros

[William Campbell]

T=addvars(T,zeros(size(T,1),1),'After',size(T,2))
Undefined function or variable 'addvars'.

?

[madhan ravi]

Because addvars() was introduced in 2018a so try the below:

N=table2cell(T);
Tnew=cell2table([N num2cell(zeros(size(T,1),1))])

Note: In the future when asking a question please mention the version which you are using in the field "Release".

[William Campbell]

Thanks that has worked for the zeros

All i want to do now is replicate the 4th column and it can go anywhere in the data but it just has to be replicated somewhere

Thanks again!

2018010100.00000	153	0	-4.70000000000000	72.5000000000000	0.500000000000000	231	0
2018010101.00000	153	0	-6.40000000000000	91.5000000000000	0.300000000000000	5	0
2018010102.00000	153	0	-6.20000000000000	94	0.700000000000000	61	0
2018010103.00000	153	0	-5.40000000000000	94	1	72	0
2018010104.00000	153	0	-5.50000000000000	98	0.600000000000000	253	0
2018010105.00000	153	0	-6.30000000000000	100	2.60000000000000	328	0
2018010106.00000	153	0	-8.10000000000000	100	7.40000000000000	327	0
2018010107.00000	157	0	-8.80000000000000	100	5.60000000000000	328	0

[madhan ravi]

OK final answer , if you have anymore questions please post a separate question:

NN=table2cell(T);
S=size(T);
New=cell(S(1),S(end)+1);
N=5; % the number of column which you want to add new values to
New(:,[1:N-1 N+1:end])=NN;
New(:,N)=NN(:,4); % copies the 4th column to where ever you it to be copied to (Nth column)
T=cell2table(New)

Answer 2

[Torsten]

A = [A A(:,4)];