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)

## █ [1:0x5cf16f295040] <tibble[,24]> 
## ├─Date=[2:0x5cf1697ff1e0] <date> 
## ├─Location=[3:0x5cf16baf5b20] <chr> 
## ├─MinTemp=[4:0x5cf16d522800] <dbl> 
## ├─MaxTemp=[5:0x5cf16e0b08c0] <dbl> 
## ├─Rainfall=[6:0x5cf16bacf2b0] <dbl> 
## ├─Evaporation=[7:0x5cf160555c40] <dbl> 
## ├─Sunshine=[8:0x5cf16d9def70] <dbl> 
## ├─WindGustDir=[9:0x5cf166cc19b0] <ord> 
## ├─WindGustSpeed=[10:0x5cf16d9052a0] <dbl> 
## ├─WindDir9am=[11:0x5cf16ca1ab00] <ord> 
## ├─WindDir3pm=[12:0x5cf16cc61dd0] <ord> 
## ├─WindSpeed9am=[13:0x5cf1676c9bc0] <dbl> 
## ├─WindSpeed3pm=[14:0x5cf16e0b2a30] <dbl> 
## ├─Humidity9am=[15:0x5cf167b502b0] <int> 
## ├─Humidity3pm=[16:0x5cf16e5d37f0] <int> 
## ├─Pressure9am=[17:0x5cf16bda4dc0] <dbl> 
## ├─Pressure3pm=[18:0x5cf16d1f51b0] <dbl> 
## ├─Cloud9am=[19:0x5cf16d155020] <int> 
## ├─Cloud3pm=[20:0x5cf16dabe570] <int> 
## ├─Temp9am=[21:0x5cf17092f100] <dbl> 
## ├─Temp3pm=[22:0x5cf16bdc6050] <dbl> 
## ├─RainToday=[23:0x5cf16e0acbe0] <fct> 
## ├─RISK_MM=[24:0x5cf16ba6fd90] <dbl> 
## └─RainTomorrow=[25:0x5cf16f28cb80] <fct>

lobstr::ref(ds)

## █ [1:0x5cf172e0ce10] <tibble[,24]> 
## ├─date=[2:0x5cf167164e80] <date> 
## ├─location=[3:0x5cf169a257c0] <chr> 
## ├─min_temp=[4:0x5cf169e11910] <dbl> 
## ├─max_temp=[5:0x5cf169fccaf0] <dbl> 
## ├─rainfall=[6:0x5cf168bce5d0] <dbl> 
## ├─evaporation=[7:0x5cf168d897b0] <dbl> 
## ├─sunshine=[8:0x5cf16aaf9600] <dbl> 
## ├─wind_gust_dir=[9:0x5cf16a187cd0] <ord> 
## ├─wind_gust_speed=[10:0x5cf16acb47e0] <dbl> 
## ├─wind_dir_9am=[11:0x5cf1698379b0] <ord> 
## ├─wind_dir_3pm=[12:0x5cf16992f640] <ord> 
## ├─wind_speed_9am=[13:0x5cf16ae6f9c0] <dbl> 
## ├─wind_speed_3pm=[14:0x5cf1690da0d0] <dbl> 
## ├─humidity_9am=[15:0x5cf16aa03480] <int> 
## ├─humidity_3pm=[16:0x5cf167320060] <int> 
## ├─pressure_9am=[17:0x5cf1692952b0] <dbl> 
## ├─pressure_3pm=[18:0x5cf169450490] <dbl> 
## ├─cloud_9am=[19:0x5cf16b02aba0] <int> 
## ├─cloud_3pm=[20:0x5cf169be09a0] <int> 
## ├─temp_9am=[21:0x5cf16960b670] <dbl> 
## ├─temp_3pm=[22:0x5cf16b60ac50] <dbl> 
## ├─rain_today=[23:0x5cf1685d3540] <fct> 
## ├─risk_mm=[24:0x5cf16b7c5e30] <dbl> 
## └─rain_tomorrow=[25:0x5cf168f44990] <fct>

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