10.41 Effect on Data Storage

20180721 When the names of the variables within a dataset are changed R does not make a complete new copy of the dataset. Instead, the actual data in the column remains in tack whilst the variable itself (ds) references a new memory location where the new variable names get noted. The underlying data within the table is unaffected.

lobstr::ref(weather)

## █ [1:0x5c868770b650] <tibble[,24]> 
## ├─Date=[2:0x5c8682fa4d60] <date> 
## ├─Location=[3:0x5c867afda680] <chr> 
## ├─MinTemp=[4:0x5c868770a9a0] <dbl> 
## ├─MaxTemp=[5:0x5c8689218990] <dbl> 
## ├─Rainfall=[6:0x5c86775d76b0] <dbl> 
## ├─Evaporation=[7:0x5c8687c137d0] <dbl> 
## ├─Sunshine=[8:0x5c8682c66ae0] <dbl> 
## ├─WindGustDir=[9:0x5c86841ceab0] <ord> 
## ├─WindGustSpeed=[10:0x5c8689151d50] <dbl> 
## ├─WindDir9am=[11:0x5c8684f901c0] <ord> 
## ├─WindDir3pm=[12:0x5c8677688880] <ord> 
## ├─WindSpeed9am=[13:0x5c867a8c9eb0] <dbl> 
## ├─WindSpeed3pm=[14:0x5c8684ad78b0] <dbl> 
## ├─Humidity9am=[15:0x5c8684411850] <int> 
## ├─Humidity3pm=[16:0x5c867dec1910] <int> 
## ├─Pressure9am=[17:0x5c8685553350] <dbl> 
## ├─Pressure3pm=[18:0x5c8684efd520] <dbl> 
## ├─Cloud9am=[19:0x5c868427acf0] <int> 
## ├─Cloud3pm=[20:0x5c868370f0f0] <int> 
## ├─Temp9am=[21:0x5c86776b3020] <dbl> 
## ├─Temp3pm=[22:0x5c8684159b40] <dbl> 
## ├─RainToday=[23:0x5c8682b93cf0] <fct> 
## ├─RISK_MM=[24:0x5c86775e8c40] <dbl> 
## └─RainTomorrow=[25:0x5c8689216470] <fct>

lobstr::ref(ds)

## █ [1:0x5c86866efbc0] <tibble[,24]> 
## ├─date=[2:0x5c867ebb0d00] <date> 
## ├─location=[3:0x5c868099ff20] <chr> 
## ├─min_temp=[4:0x5c867e0e83a0] <dbl> 
## ├─max_temp=[5:0x5c86819485e0] <dbl> 
## ├─rainfall=[6:0x5c867fc481c0] <dbl> 
## ├─evaporation=[7:0x5c867fe033a0] <dbl> 
## ├─sunshine=[8:0x5c8681c09270] <dbl> 
## ├─wind_gust_dir=[9:0x5c86807b85e0] <ord> 
## ├─wind_gust_speed=[10:0x5c8681dc4450] <dbl> 
## ├─wind_dir_9am=[11:0x5c86808ae1f0] <ord> 
## ├─wind_dir_3pm=[12:0x5c867e2a3580] <ord> 
## ├─wind_speed_9am=[13:0x5c8680d814c0] <dbl> 
## ├─wind_speed_3pm=[14:0x5c8680f3c6a0] <dbl> 
## ├─humidity_9am=[15:0x5c8681b037c0] <int> 
## ├─humidity_3pm=[16:0x5c8680c25620] <int> 
## ├─pressure_9am=[17:0x5c867f217af0] <dbl> 
## ├─pressure_3pm=[18:0x5c867f3d2cd0] <dbl> 
## ├─cloud_9am=[19:0x5c867e7ecec0] <int> 
## ├─cloud_3pm=[20:0x5c867f58deb0] <int> 
## ├─temp_9am=[21:0x5c8680072240] <dbl> 
## ├─temp_3pm=[22:0x5c868022d420] <dbl> 
## ├─rain_today=[23:0x5c867f66b7c0] <fct> 
## ├─risk_mm=[24:0x5c86803e8600] <dbl> 
## └─rain_tomorrow=[25:0x5c86805a37e0] <fct>

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