# How to sort a part of a given array?

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Lukas Hablowetz on 7 Dec 2022
Edited: Jonas on 12 Dec 2022
Hello,
I´m looking for a way to sort only a part of a given numeric array in Simulink. Lets say I´ve got an array with 20 elements [20 ... 1]. Depending on the application I just want to sort the first n [5] entries [20 19 18 17 16] in ascending order, so after the sorting the result of the entire array should look like [16 17 18 19 20 15 14 13...1].
Is there a Simulink block which already has this feature? I´m used to the sort block of the DSP toolbox but this only deals with the entire array at once.
Restrictions:
- Solution must be portable to Simulink
- the number n varies during the run-time of my application. It´s a paramter that can be adjust within 1 and 20
- the applicatoin will be converted to a C-Application by the embedded coder so there are also the given C restrictions of fixed array sizes
If there is no block I´d be glad to get any advice, how I could solve this efficiently.

Karim on 7 Dec 2022
Hi, below you can find some example code to demonstrate how to sort the first 'nSort' elements of a given vector.
% create a vector with 20 random integers
MyVec = randi(100,1,20)
MyVec = 1×20
30 30 52 14 12 19 40 15 31 100 60 72 33 16 28 1 55 5 72 39
% define the number of elements we want to sort
nSort = 5;
% sort the first 'nSort' elements:
MyVec(1:nSort) = sort(MyVec(1:nSort),'ascend')
MyVec = 1×20
12 14 30 30 52 19 40 15 31 100 60 72 33 16 28 1 55 5 72 39
Lukas Hablowetz on 12 Dec 2022
Unfortunately not, I added some restrictions to the inital description.
But I´ll try to catch up your idea.

Jonas on 7 Dec 2022
just use indexing to reassign those numbers
data=20:-1:1
data = 1×20
20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
data(1:5)=sort(data(1:5),'ascend')
data = 1×20
16 17 18 19 20 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
##### 2 CommentsShowHide 1 older comment
Jonas on 12 Dec 2022
Edited: Jonas on 12 Dec 2022
without beeing familiar with Simulink, there may be a method to split the vector into two parts, sort the first part and combine them again?
this could be suitable?

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