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)

## █ [1:0x5d452a877ac0] <tibble[,24]> 
## ├─Date=[2:0x5d45291e4b30] <date> 
## ├─Location=[3:0x5d45291e56e0] <chr> 
## ├─MinTemp=[4:0x5d452a876f10] <dbl> 
## ├─MaxTemp=[5:0x5d45291e6e40] <dbl> 
## ├─Rainfall=[6:0x5d45291e79f0] <dbl> 
## ├─Evaporation=[7:0x5d45291e85a0] <dbl> 
## ├─Sunshine=[8:0x5d45291e9150] <dbl> 
## ├─WindGustDir=[9:0x5d45291e9d00] <ord> 
## ├─WindGustSpeed=[10:0x5d45291ea2f0] <dbl> 
## ├─WindDir9am=[11:0x5d45291eaea0] <ord> 
## ├─WindDir3pm=[12:0x5d45291eb490] <ord> 
## ├─WindSpeed9am=[13:0x5d45291eba80] <dbl> 
## ├─WindSpeed3pm=[14:0x5d45291ec630] <dbl> 
## ├─Humidity9am=[15:0x5d45291ed1e0] <int> 
## ├─Humidity3pm=[16:0x5d45291ed7d0] <int> 
## ├─Pressure9am=[17:0x5d45291eddc0] <dbl> 
## ├─Pressure3pm=[18:0x5d45291ee970] <dbl> 
## ├─Cloud9am=[19:0x5d45291ef520] <int> 
## ├─Cloud3pm=[20:0x5d45291efb10] <int> 
## ├─Temp9am=[21:0x5d45291f0100] <dbl> 
## ├─Temp3pm=[22:0x5d45291f0cb0] <dbl> 
## ├─RainToday=[23:0x5d45291f1860] <fct> 
## ├─RISK_MM=[24:0x5d45291f1e50] <dbl> 
## └─RainTomorrow=[25:0x5d45291f2a00] <fct>

lobstr::ref(ds)

## █ [1:0x5d4526b74f60] <tibble[,24]> 
## ├─date=[2:0x5d4520037250] <date> 
## ├─location=[3:0x5d45220fd750] <chr> 
## ├─min_temp=[4:0x5d4522294b00] <dbl> 
## ├─max_temp=[5:0x5d452197a660] <dbl> 
## ├─rainfall=[6:0x5d4521b11a10] <dbl> 
## ├─evaporation=[7:0x5d4520b46640] <dbl> 
## ├─sunshine=[8:0x5d4520cdd9f0] <dbl> 
## ├─wind_gust_dir=[9:0x5d4521efc8f0] <ord> 
## ├─wind_gust_speed=[10:0x5d4520e74da0] <dbl> 
## ├─wind_dir_9am=[11:0x5d4521ff8670] <ord> 
## ├─wind_dir_3pm=[12:0x5d45201ce600] <ord> 
## ├─wind_speed_9am=[13:0x5d452100c150] <dbl> 
## ├─wind_speed_3pm=[14:0x5d45211a3500] <dbl> 
## ├─humidity_9am=[15:0x5d452133a8b0] <int> 
## ├─humidity_3pm=[16:0x5d45214062b0] <int> 
## ├─pressure_9am=[17:0x5d45214d1cb0] <dbl> 
## ├─pressure_3pm=[18:0x5d4521669060] <dbl> 
## ├─cloud_9am=[19:0x5d4522f09310] <int> 
## ├─cloud_3pm=[20:0x5d4522fd4d10] <int> 
## ├─temp_9am=[21:0x5d45230a0710] <dbl> 
## ├─temp_3pm=[22:0x5d4523237ac0] <dbl> 
## ├─rain_today=[23:0x5d45233cee70] <fct> 
## ├─risk_mm=[24:0x5d452349a870] <dbl> 
## └─rain_tomorrow=[25:0x5d4523631c20] <fct>

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