## ----setup, include = FALSE---------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## ----eval=FALSE, echo=TRUE----------------------------------------------------
# library(libr)
# 
# # Create temp directory
# tmp <- tempdir()
# 
# # Save some data to temp directory
# # for illustration purposes
# saveRDS(trees, file.path(tmp, "trees.rds"))
# saveRDS(rock, file.path(tmp, "rocks.rds"))
# 
# # Create library
# libname(dat, tmp)
# # library 'dat': 2 items
# # - attributes: not loaded
# # - path: C:\Users\User\AppData\Local\Temp\RtmpCSJ6Gc
# # - items:
# #    Name Extension Rows Cols   Size        LastModified
# # 1 rocks       rds   48    4 3.1 Kb 2020-11-05 23:25:34
# # 2 trees       rds   31    3 2.4 Kb 2020-11-05 23:25:34
# 
# # Examine data dictionary for library
# dictionary(dat)
# # A tibble: 7 x 9
# #   Name  Column Class   Label Description Format Width  Rows   NAs
# #   <chr> <chr>  <chr>   <lgl> <lgl>       <lgl>  <lgl> <int> <int>
# # 1 rocks area   integer NA    NA          NA     NA       48     0
# # 2 rocks peri   numeric NA    NA          NA     NA       48     0
# # 3 rocks shape  numeric NA    NA          NA     NA       48     0
# # 4 rocks perm   numeric NA    NA          NA     NA       48     0
# # 5 trees Girth  numeric NA    NA          NA     NA       31     0
# # 6 trees Height numeric NA    NA          NA     NA       31     0
# # 7 trees Volume numeric NA    NA          NA     NA       31     0
# 
# # Load library
# lib_load(dat)
# 
# # Examine workspace
# ls()
# # [1] "dat" "dat.rocks" "dat.trees" "tmp"
# 
# # Use data from the library
# summary(dat.rocks)
# #      area            peri            shape              perm
# # Min.   : 1016   Min.   : 308.6   Min.   :0.09033   Min.   :   6.30
# # 1st Qu.: 5305   1st Qu.:1414.9   1st Qu.:0.16226   1st Qu.:  76.45
# # Median : 7487   Median :2536.2   Median :0.19886   Median : 130.50
# # Mean   : 7188   Mean   :2682.2   Mean   :0.21811   Mean   : 415.45
# # 3rd Qu.: 8870   3rd Qu.:3989.5   3rd Qu.:0.26267   3rd Qu.: 777.50
# # Max.   :12212   Max.   :4864.2   Max.   :0.46413   Max.   :1300.00
# 
# # Add data to the library
# dat.trees_subset <- subset(dat.trees, Girth > 11)
# 
# # Add more data to the library
# dat.cars <- mtcars
# 
# # Unload the library from memory
# lib_unload(dat)
# 
# # Examine workspace again
# ls()
# # [1] "dat" "tmp"
# 
# # Write the library to disk
# lib_write(dat)
# # library 'dat': 4 items
# # - attributes: not loaded
# # - path: C:\Users\User\AppData\Local\Temp\RtmpCSJ6Gc
# # - items:
# #           Name Extension Rows Cols   Size        LastModified
# # 1        rocks       rds   48    4 3.1 Kb 2020-11-05 23:37:45
# # 2        trees       rds   31    3 2.4 Kb 2020-11-05 23:37:45
# # 3         cars       rds   32   11 7.3 Kb 2020-11-05 23:37:45
# # 4 trees_subset       rds   23    3 1.8 Kb 2020-11-05 23:37:45
# 
# # Clean up
# lib_delete(dat)
# 
# # Examine workspace again
# ls()
# # [1] "tmp"