Group values in a vector

Hi,

I have a long column vector ('trialnr', attached), whose elements are integer numbers from 1 to 55 (they index events in time-series).

I want to further concetenate the elements into groups (1-2, 3-4, 5-6, etc) so that I create blocks of rest-movement. The new vector will have the same size as the original.

Therefore, I want 1-2 to be 1, 3-4 to be 2 and so forth.

Any help would be great, thank you!

for example: if length(trialnr(trialnr==1)) is 7765 and length(trialnr(trialnr==2)) is 3548, then in the column vector these will be designated as 1 with length 7765+13548=11313.

[Star Strider]

I don’t see how this is going to work, since the ranges of the various elements (numbers of the individual elements) in the vector, although consecutive, are different —

LD = load('trialnr');
trialnr = LD.trialnr;
[Elements,Startidx,ic] = unique(trialnr, 'stable');
Lengths = diff([Startidx; size(trialnr,1)]);
LenvTable = table(Elements,Startidx,Lengths)

LenvTable = 55×3 table
    Elements    Startidx    Lengths
    ________    ________    _______

        1            1       7765  
        2         7766       3548  
        3        11314       4224  
        4        15538       4710  
        5        20248       3772  
        6        24020       1808  
        7        25828       1881  
        8        27709       1114  
        9        28823       2756  
       10        31579       1066  
       11        32645       2805  
       12        35450       1065  
       13        36515       3240  
       14        39755       1162  
       15        40917       1874  
       16        42791       1517  

.

Answer 1

[DGM]

I'm not sure if this is what you're asking for, but:

V = [1 1 1 2 2 2 3 3 3 4 4 4 5 5 5]

V = 1×15

1 1 1 2 2 2 3 3 3 4 4 4 5 5 5

V = ceil(V/2)

V = 1×15

1 1 1 1 1 1 2 2 2 2 2 2 3 3 3

[Panos Kerezoudis]

that works great, thank you so much!