10.13 Extract Column as Vector

20200813 To extract a single column from a dataset and return it as a vector rather than as a dataset column we can use dplyr::pull().

In the example below all of the values of a particular column are pulled and we retain just the data.table::unique() values from the resulting vector.

Using a tee pipe, the first pipe (between the curly brackets) will print a number of the locations, whilst the continuing pipe flows the vector on to be assigned into a variable for later use.

ds %>%
  pull(location) %>%
  unique() %T>%
  {head(., 20) %>% print()} ->
locations

##  [1] "Albury"        "BadgerysCreek" "Cobar"         "CoffsHarbour" 
##  [5] "Moree"         "Newcastle"     "NorahHead"     "NorfolkIsland"
##  [9] "Penrith"       "Richmond"      "Sydney"        "SydneyAirport"
## [13] "WaggaWagga"    "Williamtown"   "Wollongong"    "Canberra"     
## [17] "Tuggeranong"   "MountGinini"   "Ballarat"      "Bendigo"

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