Euclidean distance of two vectors

Question

How do I find the Euclidean distance of two vectors   x1  lt - rnorm 30  x2  lt - rnorm 30

User · Answer

As defined on Wikipedia  this should do it   euc dist  lt - function x1  x2  sqrt sum  x1 - x2    2     There s also the rdist function in the fields package that may be useful  See here     EDIT  Changed    operator to    Thanks  Gavin

User · Answer

If you want to use less code  you can also use the norm in the stats package  the  F  stands for Forbenius  which is the Euclidean norm    norm matrix x1-x2    F     While this may look a bit neater  it s not faster  Indeed  a quick test on very large vectors shows little difference  though so12311 s method is slightly faster  We first define   set seed 1234  x1  lt - rnorm 300000000  x2  lt - rnorm 300000000    Then testing for time yields the following    gt  system time a lt -sqrt sum  x1-x2  2    user  system elapsed  1 02    0 12    1 18   gt  system time b lt -norm matrix x1-x2    F    user  system elapsed  0 97    0 33    1 31

User · Answer

try using this   sqrt sum  x1-x2  2

User · Answer

Use the dist   function  but you need to form a matrix from the two inputs for the first argument to dist     dist rbind x1  x2     For the input in the OP s question we get    gt  dist rbind x1  x2           x1 x2 7 94821   a single value that is the Euclidean distance between x1 and x2

[r] Euclidean distance of two vectors

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