How to expand a table with more columns?

I have a table T1 with a size of 30000 x 55.

How do I add 6 more columns of this table: A, B, C, D, E, F, each of them have a size of 300000 x 1.

I tried to first form a new table

T2 = table(A, B, C, E, E, F);

and then join them together:

T_new = join(T1, T2);

Here is the error:

Error using tabular/join (line 130)
Cannot find a common table variable to use as a key variable.

Answer 1

[Dave B]

You can use the [ ] syntax to concatenate them, just like with a matrix (make sure that they don't share variable names):

a=rand(10,1);
b=rand(10,1);
T1=table(a,b)

T1 = 10×2 table
       a           b    
    ________    ________

    0.015889    0.086344
     0.22894    0.025285
     0.22153      0.9393
     0.82498     0.61865
     0.91705      0.6433
     0.41519     0.92073
     0.33342     0.29499
     0.83374     0.50394
     0.60389     0.27498
     0.98084     0.85301

c=rand(10,1);
d=rand(10,1);
T2=table(c,d)

T2 = 10×2 table
       c          d    
    _______    ________

    0.73747     0.53457
    0.55264      0.8379
    0.50305     0.66591
    0.95375     0.15684
    0.18068     0.57932
     0.6631     0.57374
    0.48546     0.12394
    0.15803     0.61982
    0.12944      0.4348
    0.62464    0.087705

T3=[T1 T2]

T3 = 10×4 table
       a           b           c          d    
    ________    ________    _______    ________

    0.015889    0.086344    0.73747     0.53457
     0.22894    0.025285    0.55264      0.8379
     0.22153      0.9393    0.50305     0.66591
     0.82498     0.61865    0.95375     0.15684
     0.91705      0.6433    0.18068     0.57932
     0.41519     0.92073     0.6631     0.57374
     0.33342     0.29499    0.48546     0.12394
     0.83374     0.50394    0.15803     0.61982
     0.60389     0.27498    0.12944      0.4348
     0.98084     0.85301    0.62464    0.087705

Alternatively, if you want to use join, you just need something to join them on (something which identfies which rows are the same in the two tables). You can use an existing index variable, or the RowNames property for this:

T1.Properties.RowNames=string(1:height(T1))';
T2.Properties.RowNames=string(1:height(T2))';
T4=join(T1,T2,'Keys','Row')

T4 = 10×4 table
             a           b           c          d    
          ________    ________    _______    ________

    1     0.015889    0.086344    0.73747     0.53457
    2      0.22894    0.025285    0.55264      0.8379
    3      0.22153      0.9393    0.50305     0.66591
    4      0.82498     0.61865    0.95375     0.15684
    5      0.91705      0.6433    0.18068     0.57932
    6      0.41519     0.92073     0.6631     0.57374
    7      0.33342     0.29499    0.48546     0.12394
    8      0.83374     0.50394    0.15803     0.61982
    9      0.60389     0.27498    0.12944      0.4348
    10     0.98084     0.85301    0.62464    0.087705

[Leon]

Many thanks!