How to create an empty R vector to add new items

Question

I want to use R in Python  as provided by the module Rpy2  I notice that R has very convenient    operations by which you can extract the specific columns or lines  How could I achieve such a function by Python scripts   My idea is to create an R vector and add those wanted elements into this vector so that the final vector is the same as that in R  I created a seq    but it seems that it has an initial digit 1  so the final result would always start with the digit 1  which is not what I want  So  is there a better way to do this

User · Answer

I pre-allocate a vector with   gt   a  lt - rep NA  10     1  NA NA NA NA NA NA NA NA NA NA   You can then use    to insert values into it

User · Answer

You can create an empty vector like so  vec  lt - numeric 0    And then add elements using c    vec  lt - c vec  1 5    However as romunov says  it s much better to pre-allocate a vector and then populate it  as this avoids reallocating a new copy of your vector every time you add elements

User · Answer

To create an empty vector use   vec  lt - c      Please note  I am not making any assumptions about the type of vector you require  e g  numeric   Once the vector has been created you can add elements to it as follows   For example  to add the numeric value 1   vec  lt - c vec  1     or  to add a string value  a   vec  lt - c vec   a

User · Answer

As pointed out by Brani  vector   is a solution  e g   newVector  lt - vector mode    numeric   length   50   will return a vector named  newVector  with 50  0  s as initial values  It is also fairly common to just add the new scalar to an existing vector to arrive at an expanded vector  e g   aVector  lt - c aVector  newScalar

User · Answer

In rpy2  the way to get the very same operator as     with R is to use   rx   See the documentation about extracting with rpy2  For creating vectors  if you know your way around with Python there should not be any issue  See the documentation about creating vectors

User · Answer

vec  lt - vector     See also vector help   vector

User · Answer

I ve also seen  x  lt -      Now  you can concatenate or bind  a vector of any dimension to x  rbind x  1 10  cbind x  1 10  c x  10

[python] How to create an empty R vector to add new items

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