How to delete columns from something that isn't a matrix

I've got some data that I need columns deleting from, specificially 3,4,5,9,10,12,13,14 but whenever I try the following code, with data set A, I get the answer "Deletion requires an existing variable."

 A(:,[3 4 5 9 10 12 13 14])=[];

Is this because my data is not technically a matrix?

Below is some of my data

 2018-01-01T00:00 273.450   2.350 -999.000 -999.000 -999.000 -999.000 -999.000  -1.000 -999.000 -999.000   0.000 -999.000 -999.000 -999.000
2018-01-01T01:00 273.250   1.570 -999.000 -999.000 -999.000 -999.000 -999.000  -1.000 -999.000 -999.000   0.000 -999.000 -999.000 -999.000
2018-01-01T02:00 273.350   0.510 -999.000 -999.000 -999.000 -999.000 -999.000  -1.000 -999.000 -999.000   0.000 -999.000 -999.000 -999.000
2018-01-01T03:00 273.250   1.420 -999.000 -999.000 -999.000 -999.000 -999.000  -1.000 -999.000 -999.000   0.000 -999.000 -999.000 -999.000
2018-01-01T04:00 273.350   0.140 -999.000 -999.000 -999.000 -999.000 -999.000  -1.000 -999.000 -999.000   0.000 -999.000 -999.000 -999.000
2018-01-01T05:00 275.550   0.700 -999.000 -999.000 -999.000 -999.000 -999.000  -1.000 -999.000 -999.000   0.000 -999.000 -999.000 -999.000

Thanks!

[Adam]

What does

whos

show when run on command line? The text of the error message suggests that A does not exist at all rather than anything to do with what type of variable it is.

[William Campbell]

whos
  Name      Size            Bytes  Class     Attributes

  A         4x4               128  double              
  ans       1x4                 8  char                

Answer 1

[madhan ravi]

EDITED

T=readtable('sample.txt'); % your filename
T(:,[3 4 5 9 10 12 13 14])=[] 

Gives:

 T =

  6×7 table

           Var1            Var2     Var6    Var7    Var8    Var11    Var15
    __________________    ______    ____    ____    ____    _____    _____

    '2018-01-01T00:00'    273.45    -999    -999    -999    -999     -999 
    '2018-01-01T01:00'    273.25    -999    -999    -999    -999     -999 
    '2018-01-01T02:00'    273.35    -999    -999    -999    -999     -999 
    '2018-01-01T03:00'    273.25    -999    -999    -999    -999     -999 
    '2018-01-01T04:00'    273.35    -999    -999    -999    -999     -999 
    '2018-01-01T05:00'    275.55    -999    -999    -999    -999     -999 
    

Note: Download the attached document and try my code.

[William Campbell]

Hi Madhan

Thanks for responding so quickly but when i put the first line I get this answer

Error using readtable (line 198)

Unable to open file 'sample.txt'.

Thanks

[madhan ravi]

Anytime :) , see edited answer.

[William Campbell]

Yeah so my data filename is SLFSLFmeta

here is a picture of what I am doing, am I doing something very stupid?

[madhan ravi]

Your data filename should be SLFSLFmeta.txt not SLFSLFmeta

Which version are you using?

[William Campbell]

Hi again Madhan

for some reason it only worked when I exlcuded .txt from it? like it worked with SLFSLFmeta

It has worked now but my time in ISO format has come up in apostrophes like yours did, is there a way I can get rid of these? thanks

and version 9.3.0.713579 (R2017b)

[madhan ravi]

T=readtable('sample.txt'); % your filename
T(:,[3 4 5 9 10 12 13 14])=[];  
T.Var1=datetime(T.Var1,'Format','yyyy-MM-dd''T''mm:ss')

Gives:

T =

  6×7 table

          Var1           Var2     Var6    Var7    Var8    Var11    Var15
    ________________    ______    ____    ____    ____    _____    _____

    2018-01-01T00:00    273.45    -999    -999    -999    -999     -999 
    2018-01-01T01:00    273.25    -999    -999    -999    -999     -999 
    2018-01-01T02:00    273.35    -999    -999    -999    -999     -999 
    2018-01-01T03:00    273.25    -999    -999    -999    -999     -999 
    2018-01-01T04:00    273.35    -999    -999    -999    -999     -999 
    2018-01-01T05:00    275.55    -999    -999    -999    -999     -999 

[William Campbell]

Thanks madhan

That's worked

how do i then export this as a textfile and not .mat ?

Thanks

Archie

[madhan ravi]

If it answered your original question ("How to delete columns from something that isn't a matrix?") make sure to accept the answer.

writetable(T,'sample.txt')

[William Campbell]

Sorry yes done

That has exported it but put commas inbetween every value in the row

How do I get rid of this?

Last question I promise!

Thanks again

[madhan ravi]

writetable(T,'sample.txt','Delimiter',' ')
writetable(T,'sample.txt','Delimiter',' ','WriteVariableNames',0) % if you want to avoid variable names

[William Campbell]

Thanks

But there are still " marks around the date?

"2018-01-01T00:00 " 273.45 2.35 -999 -999 -1 0
"2018-01-01T01:00 " 273.25 1.57 -999 -999 -1 0
"2018-01-01T02:00 " 273.35 0.51 -999 -999 -1 0
"2018-01-01T03:00 " 273.25 1.42 -999 -999 -1 0

[madhan ravi]

T=readtable('sample.txt'); % your rawdata filename 
T(:,[3 4 5 9 10 12 13 14])=[];  
T.Var1=datetime(T.Var1,'Format','yyyy-MM-dd''T''mm:ss')
writetable(T,'sample1.txt','Delimiter',' ','WriteVariableNames',0) % I don't see any strings around date