Extract every nth element of a vector

Question

I would like to create a vector in which each element is the i 6th element of another vector   For example  in a vector of length 120 I want to create another vector of length 20 in which each element is value i  i 6  i 12  i 18    of the initial vector  i e  I want to extract every 6th element of the original

User · Answer

To select every nth element from any starting position in the vector  nth element  lt - function vector  starting position  n       vector seq starting position  length vector   n           E g  vec  lt - 1 12  nth element vec  1  3     1   1  4  7 10  nth element vec  2  3     1   2  5  8 11

User · Answer

Another trick for getting sequential pieces  beyond the seq solution already mentioned  is to use a short logical vector and use vector recycling   foo  c  rep FALSE  5   TRUE

User · Answer

a  lt - 1 120 b  lt - a seq 1  length a   6

User · Answer

I think you are asking two things which are not necessarily the same     I want to extract every 6th element of   the original   You can do this by indexing a sequence   foo  lt - 1 120 foo 1 20 6         I would like to create a vector in   which each element is the i 6th   element of another vector    An easy way to do this is to supplement a logical factor with FALSEs until i 6   foo  lt - 1 120 i  lt - 1 foo 1  i 6    i 6    1    7  14  21  28  35  42  49  56  63  70  77  84  91  98 105 112 119  i  lt - 10 foo 1  i 6    i 6    1   16  32  48  64  80  96 112

[r] Extract every nth element of a vector

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