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)

## █ [1:0x589499a65d90] <tibble[,24]> 
## ├─Date=[2:0x58949340a4b0] <date> 
## ├─Location=[3:0x58949970a670] <chr> 
## ├─MinTemp=[4:0x589499a651e0] <dbl> 
## ├─MaxTemp=[5:0x589495263710] <dbl> 
## ├─Rainfall=[6:0x589497758730] <dbl> 
## ├─Evaporation=[7:0x58949886ddd0] <dbl> 
## ├─Sunshine=[8:0x5894980f20d0] <dbl> 
## ├─WindGustDir=[9:0x58949c1d2590] <ord> 
## ├─WindGustSpeed=[10:0x5894969ff3d0] <dbl> 
## ├─WindDir9am=[11:0x5894980036f0] <ord> 
## ├─WindDir3pm=[12:0x58949864cd60] <ord> 
## ├─WindSpeed9am=[13:0x589496f71fa0] <dbl> 
## ├─WindSpeed3pm=[14:0x5894920d9e10] <dbl> 
## ├─Humidity9am=[15:0x58949c256ce0] <int> 
## ├─Humidity3pm=[16:0x5894962f6160] <int> 
## ├─Pressure9am=[17:0x58948e710f20] <dbl> 
## ├─Pressure3pm=[18:0x5894986a5930] <dbl> 
## ├─Cloud9am=[19:0x58949a8f9ef0] <int> 
## ├─Cloud3pm=[20:0x589498130990] <int> 
## ├─Temp9am=[21:0x589497f58e70] <dbl> 
## ├─Temp3pm=[22:0x58948ca35250] <dbl> 
## ├─RainToday=[23:0x589499038360] <fct> 
## ├─RISK_MM=[24:0x58948e30e010] <dbl> 
## └─RainTomorrow=[25:0x589493b183f0] <fct>

lobstr::ref(ds)

## █ [1:0x5894a16063c0] <tibble[,24]> 
## ├─date=[2:0x589493faeb20] <date> 
## ├─location=[3:0x58949441c960] <chr> 
## ├─min_temp=[4:0x589491c89ed0] <dbl> 
## ├─max_temp=[5:0x5894947e3f30] <dbl> 
## ├─rainfall=[6:0x58949499f110] <dbl> 
## ├─evaporation=[7:0x58949358e270] <dbl> 
## ├─sunshine=[8:0x589493749450] <dbl> 
## ├─wind_gust_dir=[9:0x589494327500] <ord> 
## ├─wind_gust_speed=[10:0x589493904630] <dbl> 
## ├─wind_dir_9am=[11:0x5894946ad050] <ord> 
## ├─wind_dir_3pm=[12:0x589491e450b0] <ord> 
## ├─wind_speed_9am=[13:0x589495413460] <dbl> 
## ├─wind_speed_3pm=[14:0x5894955ce640] <dbl> 
## ├─humidity_9am=[15:0x589494b5a2f0] <int> 
## ├─humidity_3pm=[16:0x589492fbb660] <int> 
## ├─pressure_9am=[17:0x589495789820] <dbl> 
## ├─pressure_3pm=[18:0x589495944a00] <dbl> 
## ├─cloud_9am=[19:0x5894924a72b0] <int> 
## ├─cloud_3pm=[20:0x589495affbe0] <int> 
## ├─temp_9am=[21:0x589495bdd4f0] <dbl> 
## ├─temp_3pm=[22:0x589495d986d0] <dbl> 
## ├─rain_today=[23:0x589495f538b0] <fct> 
## ├─risk_mm=[24:0x5894960311c0] <dbl> 
## └─rain_tomorrow=[25:0x5894961ec3a0] <fct>

---

Your donation will support ongoing availability and give you access to the PDF version of this book. Desktop Survival Guides include Data Science, GNU/Linux, and MLHub. Books available on Amazon include Data Mining with Rattle and Essentials of Data Science. Popular open source software includes rattle, wajig, and mlhub. Hosted by Togaware, a pioneer of free and open source software since 1984. Copyright © 1995-2022 Graham.Williams@togaware.com Creative Commons Attribution-ShareAlike 4.0