[Scilab-users] Inserting %nan at given positions into a vector

[Jens Simon Strom]

Hallo Samuel,
Tanquam ex ungue leonem! Great!

Kind regards
Jens
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Am 05.12.2018 22:12, schrieb Samuel Gougeon:
> Le 05/12/2018 à 13:01, Jens Simon Strom a écrit :
>> Hallo Scilab experts,
>> Given is a numeric vector x of length n and an index vector i with  
>> max(i)=n. I want to insert a %nan after every x(i).
>>
>> Example
>> x=[11:20]
>> i=[2 5 8]
>> Required result: y=[11 12 %nan 13 14 15 %nan 16 17 18 %nan 19 20]
>>
>> How would you proceed so that it works fast for n>500000 too.
>
> The following code does it:
>
> x  =  11:20;
> i  =[2  5  8];
> //                   [11 12      13 14 15      16 17 18      19 20]
> //Required result: y=[11 12 %nan 13 14 15 %nan 16 17 18 %nan 19 20]
> nx  =  size(x,"*");
> ni  =  size(i,"*");
> o  =  ones(1,nx);
> o(i+1)  =  2;
> newx  =  zeros(1,nx+ni);
> newx(cumsum(o))  =  x;
> newx(i+(1:ni))  =  %nan
>
> --> newx(i+(1:ni)) = %nan
>   newx  =
>     11.   12.   Nan   13.   14.   15.   Nan   16.   17.   18.   Nan   19.   20.
>
> Regards
> Samuel
>
>
>
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