Checking column types
It's a good idea to check our column types and make sure nothing strange stands out. In addition to column types, the rxGetInfo function also shows lows and highs for numeric columns, which can be useful for identifying outliers or running sanity checks. With the numRows = 10 argument, we can look at the first 10 rows of the data as well.
rxGetInfo(nyc_xdf, getVarInfo = TRUE, numRows = 5) # show column types and the first 10 rows
File name: C:\Data\NYC_taxi\yellow_tripdata_2016.xdf
Number of observations: 69406520
Number of variables: 19
Number of blocks: 141
Compression type: zlib
Variable information:
Var 1: VendorID 2 factor levels: 2 1
Var 2: tpep_pickup_datetime, Type: character
Var 3: tpep_dropoff_datetime, Type: character
Var 4: passenger_count, Type: integer, Low/High: (0, 9)
Var 5: trip_distance, Type: numeric, Low/High: (-3390583.8000, 19072628.8000)
Var 6: pickup_longitude, Type: numeric, Low/High: (-165.0819, 118.4089)
Var 7: pickup_latitude, Type: numeric, Low/High: (-77.0395, 66.8568)
Var 8: RatecodeID, Type: integer, Low/High: (1, 99)
Var 9: store_and_fwd_flag 2 factor levels: N Y
Var 10: dropoff_longitude, Type: numeric, Low/High: (-161.6987, 106.2469)
Var 11: dropoff_latitude, Type: numeric, Low/High: (-77.0395, 405.3167)
Var 12: payment_type 5 factor levels: 2 1 3 4 5
Var 13: fare_amount, Type: numeric, Low/High: (-957.6000, 628544.7400)
Var 14: extra, Type: numeric, Low/High: (-58.5000, 648.8700)
Var 15: mta_tax, Type: numeric, Low/High: (-2.7000, 89.7000)
Var 16: tip_amount, Type: numeric, Low/High: (-220.8000, 998.1400)
Var 17: tolls_amount, Type: numeric, Low/High: (-99.9900, 1410.3200)
Var 18: improvement_surcharge, Type: numeric, Low/High: (-0.3000, 11.6400)
Var 19: total_amount, Type: numeric, Low/High: (-958.4000, 629033.7800)
Data (5 rows starting with row 1):
VendorID tpep_pickup_datetime tpep_dropoff_datetime passenger_count trip_distance
1 2 2016-01-01 00:00:00 2016-01-01 00:00:00 2 1.10
2 2 2016-01-01 00:00:00 2016-01-01 00:00:00 5 4.90
3 2 2016-01-01 00:00:00 2016-01-01 00:00:00 1 10.54
4 2 2016-01-01 00:00:00 2016-01-01 00:00:00 1 4.75
5 2 2016-01-01 00:00:00 2016-01-01 00:00:00 3 1.76
pickup_longitude pickup_latitude RatecodeID store_and_fwd_flag dropoff_longitude
1 -73.99037 40.73470 1 N -73.98184
2 -73.98078 40.72991 1 N -73.94447
3 -73.98455 40.67957 1 N -73.95027
4 -73.99347 40.71899 1 N -73.96224
5 -73.96062 40.78133 1 N -73.97726
dropoff_latitude payment_type fare_amount extra mta_tax tip_amount tolls_amount
1 40.73241 2 7.5 0.5 0.5 0 0
2 40.71668 1 18.0 0.5 0.5 0 0
3 40.78893 1 33.0 0.5 0.5 0 0
4 40.65733 2 16.5 0.0 0.5 0 0
5 40.75851 2 8.0 0.0 0.5 0 0
improvement_surcharge total_amount
1 0.3 8.8
2 0.3 19.3
3 0.3 34.3
4 0.3 17.3
5 0.3 8.8