Sys.setenv("RETICULATE_PYTHON" = "C:\\Users\\leungi\\AppData\\Local\\Continuum\\anaconda3\\python.exe")
reticulate::py_config()
#> python:         C:\Users\leungi\AppData\Local\Continuum\anaconda3\python.exe
#> libpython:      C:/Users/leungi/AppData/Local/Continuum/anaconda3/python37.dll
#> pythonhome:     C:\Users\leungi\AppData\Local\CONTIN~1\ANACON~1
#> version:        3.7.3 (default, Apr 24 2019, 15:29:51) [MSC v.1915 64 bit (AMD64)]
#> Architecture:   64bit
#> numpy:          C:\Users\leungi\AppData\Local\CONTIN~1\ANACON~1\lib\site-packages\numpy
#> numpy_version:  1.16.4
#> 
#> NOTE: Python version was forced by RETICULATE_PYTHON

library(googler)
googler("rstats")
#> Warning in file.remove("NUL"): cannot remove file 'NUL', reason 'Permission
#> denied'
#> Error in windows_python(): object 'path' not found

# inspecting issue
googler:::windows_python()
#> Warning in file.remove("NUL"): cannot remove file 'NUL', reason 'Permission
#> denied'
#> Error in googler:::windows_python(): object 'path' not found

# checking windows_python()
windows_python <- function(x) {
  if (!grepl("python", googler:::sys_which("python"))) {
    stop("'googler' requires python, which does not appear to be installed.")
  }
  path
}

# checking sys_which()
x <- "python"

if (googler:::is_unix()) {
  return(Sys.which(x))
}
sys_win <- function(x) {
  suppressWarnings({
    path <- tryCatch(
      system(sprintf("where %s", x), intern = TRUE)[1],
      error = function(e) NA_character_
    )
  })
  if (file.exists("NUL")) {
    file.remove("NUL")
  }
  if (!is.na(path)) {
    return(`names<-`(path, x))
  }
  Sys.which(x)
}
vapply(x, sys_win, character(1))
#> Warning in file.remove("NUL"): cannot remove file 'NUL', reason 'Permission
#> denied'
#>                                                                python 
#> "C:\\Users\\leungi\\AppData\\Local\\Continuum\\anaconda3\\python.exe"

## python is detected, but yet path from sys_which() is NULL

path
#> Error in eval(expr, envir, enclos): object 'path' not found

Sys.setenv("RETICULATE_PYTHON" = "C:\\Users\\leungi\\AppData\\Local\\Continuum\\anaconda3\\python.exe")
reticulate::py_config()
#> python:         C:\Users\leungi\AppData\Local\Continuum\anaconda3\python.exe
#> libpython:      C:/Users/leungi/AppData/Local/Continuum/anaconda3/python37.dll
#> pythonhome:     C:\Users\leungi\AppData\Local\CONTIN~1\ANACON~1
#> version:        3.7.3 (default, Apr 24 2019, 15:29:51) [MSC v.1915 64 bit (AMD64)]
#> Architecture:   64bit
#> numpy:          C:\Users\leungi\AppData\Local\CONTIN~1\ANACON~1\lib\site-packages\numpy
#> numpy_version:  1.16.4
#> 
#> NOTE: Python version was forced by RETICULATE_PYTHON

library(googler)

## works
googler("rstats", count = 2, lang = "en")
#> # A tibble: 2 x 4
#>   abstract                      matches    title           url             
#>   <chr>                         <list>     <chr>           <chr>           
#> 1 "5h ago @akesslerdc tweeted:~ <df[,2] [~ News about #rs~ https://twitter~
#> 2 The R Project for Statistica~ <NULL>     The R Project ~ https://www.r-p~

## works
googler("rstats", count = 2)
#> # A tibble: 2 x 4
#>   abstract                       matches    title         url              
#>   <chr>                          <list>     <chr>         <chr>            
#> 1 "5h ago @akesslerdc tweeted: ~ <df[,2] [~ News about #~ https://twitter.~
#> 2 Read writing about Rstats in ~ <df[,2] [~ Rstats – Tow~ https://towardsd~

## fails
googler("rstats")
#> Warning in system2(cmd, args = args, stdout = TRUE): running command
#> '"C:\Users\leungi\AppData\Local\Continuum\anaconda3\python.exe" C:
#> \Users\leungi\AppData\Local\Temp\RtmpEVevEU/googler "rstats" -C --json' had
#> status 1
#> Error: lexical error: invalid char in json text.
#>                                        NA
#>                      (right here) ------^