Data Science Desktop Survival Guide by Graham Williams
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Pipes: Tee Pipe Intermediate Results

20210103 A use of the tee-pipe that can come in handy is to base::assign() intermediate results into a variable without breaking the main flow of the pipeline. The variable tmp in the following tee-pipe is assigned to within the base::globalenv() so that we can access it from anywhere in the R session.

ds %>%
  select(rainfall, min_temp, max_temp, sunshine) %>%
  filter(rainfall==0) %T>%
  {assign("tmp", ., globalenv())}  %>%
  select(min_temp, max_temp, sunshine) %>%
  summary()

##     min_temp        max_temp        sunshine    
##  Min.   :-8.70   Min.   :-2.10   Min.   : 0.00  
##  1st Qu.: 7.40   1st Qu.:19.80   1st Qu.: 6.90  
##  Median :12.10   Median :24.60   Median : 9.70  
##  Mean   :12.15   Mean   :24.97   Mean   : 8.72  
##  3rd Qu.:16.90   3rd Qu.:30.00   3rd Qu.:11.10  
....

We can now access the variable tmp:

print(tmp)

## # A tibble: 112,447 x 4
##    rainfall min_temp max_temp sunshine
##       <dbl>    <dbl>    <dbl>    <dbl>
##  1        0      7.4     25.1       NA
##  2        0     12.9     25.7       NA
##  3        0      9.2     28         NA
....

Notice the use of the curly braces for the first path of the tee-pipe. This allows us to reference the data from the pipeline as the period (.).