make_refreshable {refreshr}

Making dataframes/tables refreshable

Description

Makes a dataframe/table refreshable, i.e. connects it with a data source and specifies code that is applied to the raw data after the data has been loaded (optional).

Usage

make_refreshable(df, load_code, prep_code = NULL)

Arguments

df

The dataframe/table that is to be made refreshable

load_code

The code used to load the data from the data source. Please not that quotes need to be escaped (code\").

prep_code

The code used to transform the raw data downloaded from the data source. The placeholder # can be used in this code to refer to the data downloaded from the data source.

Value

A dataframe/table of class refreshr that can be refreshed by calling refresh().

Examples

## Not run: 

library(data.table)
library(dplyr)

# Load US unemployment rate from Bureau of Labor Statistics
data <- fread("https://download.bls.gov/pub/time.series/ln/ln.data.1.AllData", sep="\t")

# Make refreshable and specify code for data preparation (filter raw data for
# the overall US employment rate) with # being a placeholder for the downloaded
# raw data
data_refresh <- make_refreshable(data,
                     load_code = "data.table::fread(
                        \"https://download.bls.gov/pub/time.series/ln/ln.data.1.AllData\",
                        sep=\"\t\")",
                     prep_code = "filter(#, series_id==\"LNS14000000\")")

# Save refreshable dataframe as RData file (e.g. to share dataset with coworkers or public)
save(data_refresh, file = "refresh.RData")

# Remove dataframe and reload it from file
rm(data_refresh)
load(file = "refresh.RData")

# Refresh the dataframe
data_refresh <- refresh(data_refresh)

# Show properties of refreshable dataframe
properties(data_refresh)

# Check if refreshable dataframe is up-to-date with the remote data source
uptodate(data_refresh)

## End(Not run)