How to join the same table multiple times

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Asked 1 year, 2 months ago

Modified 1 year, 2 months ago

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Consider some test table

tab=Table[{i,i^2},{i,1,100,1}];

I would like to obtain the table

tab2=Join[tab,tab,...,tab]

where ... include some number of tab, in a compact and smart way. Say, for 10 tab, the stupid way would be

tab2=Join[tab,tab,tab,tab,tab,tab,tab,tab,tab,tab]

Could you please tell me how to do this?

My guess is

tab[n_]:=Flatten[Table[tab2,{i,1,n,1}],1]

But I have doubts whether it will be fast in case of large tables.

asked Sep 19, 2022 at 11:23

John Taylor

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1

$\begingroup$ To do this say 20 times, tab3 = Flatten[#, 1] &@Table[tab, 20]? $\endgroup$
– Syed
Sep 19, 2022 at 11:26
2

$\begingroup$ tab4 = Catenate[Table[tab, 20]] $\endgroup$
– Syed
Sep 19, 2022 at 11:29
1

$\begingroup$ tab5 = Fold[Join, ConstantArray[tab, 20]] $\endgroup$
– Syed
Sep 19, 2022 at 11:40
1

$\begingroup$ tab6 = Sequence @@@ ConstantArray[tab, 20] $\endgroup$
– Syed
Sep 19, 2022 at 11:44
$\begingroup$ Looks like a possible x-y problem. What is the actual goal? $\endgroup$
– Alan
Sep 19, 2022 at 13:15

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1 Answer 1

Sorted by:

tab2 == Join @@ ConstantArray[tab, 10]
(*    True    *)

answered Sep 19, 2022 at 11:26

Roman

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