Do not print result when assigned to an object

[aravindhebbali]

This issue was brought to our notice by Peter B Mandeville:

I believe that generally when a calculation is made in R that the result is shown on the screen:

> 2+2
[1] 4

I also believe that generally when a calculation is made in R and the result is assigned to an object that the results isn’t shown on the screen:

> X <- 2+2
> X
[1] 4

Or

> (X <- 2+2)
[1] 4

The following code is from Packages olsrr – ols_step_forward_p. If the anterior is correct then this code ought to show the result on the screen:

# stepwise forward regression
model <- lm(y ~ ., data = surgical)
ols_step_forward_p(model)

which it does and

# stepwise forward regression plot
model <- lm(y ~ ., data = surgical)
k <- ols_step_forward_p(model)

shouldn’t show the result on the screen but it does.

It this is not an error, how can I stop showing the results on the screen when I am assigning them to an object?

These functions behave in the same way.

• ols_step_forward_p
• ols_step_backward_p
• ols_step_both_p
• ols_step_forward_aic
• ols_step_backward_aic
• ols_step_both_aic

Finally, the I detected something strange with the ols_step_both_aic function but I can’t repeat it:

model <- lm(y ~ ., data = surgical)
k <- ols_step_forward_p(model)
k$names
k$model

> k$names
NULL
> k$model

Call:
lm(formula = paste(response, "~", paste(preds, collapse = " + ")),
    data = l)

Coefficients:
(Intercept)   liver_test    alc_heavy  enzyme_test  
  -1178.330       58.064      317.848        9.748  
     pindex          bcs  
      8.924       59.864  

> sessionInfo()
R version 3.6.1 (2019-07-05)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18362)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252
[2] LC_CTYPE=English_United States.1252  
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets
[6] methods   base    

other attached packages:
[1] olsrr_0.5.2

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.3         lubridate_1.7.4  
 [3] lattice_0.20-38    tidyr_1.0.0      
 [5] clisymbols_1.2.0   class_7.3-15      
 [7] assertthat_0.2.1   zeallot_0.1.0    
 [9] digest_0.6.22      ipred_0.9-9      
[11] mime_0.7           R6_2.4.0          
[13] cellranger_1.1.0   backports_1.1.5  
[15] httr_1.4.1         ggplot2_3.2.1    
[17] pillar_1.4.2       rlang_0.4.1      
[19] lazyeval_0.2.2     curl_4.2          
[21] readxl_1.3.1       rstudioapi_0.10  
[23] data.table_1.12.6  car_3.0-4        
[25] rpart_4.1-15       Matrix_1.2-17    
[27] goftest_1.1-1      checkmate_1.9.4  
[29] splines_3.6.1      gower_0.2.1      
[31] stringr_1.4.0      foreign_0.8-72    
[33] munsell_0.5.0      shiny_1.4.0      
[35] httpuv_1.5.2       compiler_3.6.1    
[37] pkgconfig_2.0.3    htmltools_0.4.0  
[39] nnet_7.3-12        tidyselect_0.2.5  
[41] tibble_2.1.3       gridExtra_2.3    
[43] prodlim_2019.10.13 rio_0.5.16        
[45] later_1.0.0        crayon_1.3.4      
[47] dplyr_0.8.3        withr_2.1.2      
[49] MASS_7.3-51.4      recipes_0.1.7    
[51] grid_3.6.1         lifecycle_0.1.0  
[53] xtable_1.8-4       jsonlite_1.6      
[55] gtable_0.3.0       magrittr_1.5      
[57] scales_1.0.0       zip_2.0.4        
[59] stringi_1.4.3      carData_3.0-2    
[61] promises_1.1.0     timeDate_3043.102
[63] generics_0.0.2     vctrs_0.2.0      
[65] gh_1.0.1           openxlsx_4.1.3    
[67] nortest_1.0-4      lava_1.6.6        
[69] tools_3.6.1        forcats_0.4.0    
[71] glue_1.3.1         purrr_0.3.3      
[73] hms_0.5.2          fastmap_1.0.1    
[75] abind_1.4-5        survival_2.44-1.1
[77] colorspace_1.4-1   haven_2.2.0