How to include source R script in other scripts

Question

I ve created a utility R script  util R  which I want to use from other scripts in my project  What is the proper way to ensure that the function this script defines are available to function in my other scripts   I m looking for something similar to the require function  that loads a package only if it has not been loaded yet  I don t want to call source  util R   because that will load the script every time it is called   I know that I will get some answers telling me to create a package  as in Organizing R Source Code    But I m not creating something that will be used elsewhere  it is just a standalone project

User · Answer

I solved my problem using entire address where my code is  Before   if  exists  foo   mode  function    source  utils r     After   if  exists  foo   mode  function    source  C  tests utils r

User · Answer

There is no such thing built-in  since R does not track calls to source and is not able to figure out what was loaded from where  this is not the case when using packages   Yet  you may use same idea as in C  h files  i e  wrap the whole in   if  exists  util R      util R lt -T    Code

User · Answer

Here is one possible way   Use the exists function to check for something unique in your util R code   For example   if  exists  foo   mode  function    source  util R      Edited to include mode  function   as Gavin Simpson pointed out

User · Answer

Say util R produces a function foo    You can check if this function is available in the global environment and source the script if it isn t   if identical length ls pattern     foo      0       source  util R     That will find anything with the name foo  If you want to find a function  then  as mentioned by  Andrie  exists   is helpful but needs to be told exactly what type of object to look for  e g   if exists  foo   mode    function        source  util R     Here is exists   in action    gt  exists  foo   mode    function    1  FALSE  gt  foo  lt - function x  x  gt  exists  foo   mode    function    1  TRUE  gt  rm foo   gt  foo  lt - 1 10  gt  exists  foo   mode    function    1  FALSE

User · Answer

You could write a function that takes a filename and an environment name  checks to see if the file has been loaded into the environment and uses sys source to source the file if not   Here s a quick and untested function  improvements welcome     include  lt - function file  env        ensure file and env are provided   if missing file     missing env       stop   file  and  env  must be provided       ensure env is character   if  is character file      is character env       stop   file  and  env  must be a character        see if env is attached to the search path   if env  in  search          ENV  lt - get env      files  lt - get   files  ENV        if the file hasn t been loaded     if   file  in  files           sys source file  ENV                           load the file       assign   files   c file  files   envir ENV     set the flag           else       ENV  lt - attach NULL  name env         create attach new environment     sys source file  ENV                 load the file     assign   files   file  envir ENV     set the flag

User · Answer

Here is a function I wrote  It wraps the base  source function to store a list of sourced files in a global environment list named sourced  It will only re-source a file if you provide a  force TRUE argument to the call to source  Its argument signature is otherwise identical to the real source   so you don t need to rewrite your scripts to use this   warning  overriding source with my own function FYI   source  lt - function path   force FALSE           library tools    path  lt - tryCatch normalizePath path   error function e  path    m lt -md5sum path     go lt -TRUE   if   is vector  GlobalEnv sourced          GlobalEnv sourced  lt - list         if   is null  GlobalEnv sourced  path           if m     GlobalEnv sourced  path            message sprintf  Not re-sourcing  s  Override with  n  source   s    force TRUE    path  path         go lt -FALSE           else         message sprintf  re-sourcing  s as it has changed from   s to   s   path   GlobalEnv sourced  path    m         go lt -TRUE              if  force        go lt -TRUE     message       forcing          if go        message sprintf  sourcing  s   path        GlobalEnv sourced path   lt - m     base  source path               It s pretty chatty  lots of calls to message    so you can take those lines out if you care  Any advice from veteran R users is appreciated  I m pretty new to R

[r] How to include (source) R script in other scripts

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