butterfly (version 1.1.2)

catch: Catch: return dataframe containing only rows that have changed

Description

This function matches two dataframe objects by their unique identifier (usually "time" or "datetime in a timeseries), and returns a new dataframe which contains only rows that have changed compared to previous data. It will not return any new rows.

Usage

catch(df_current, df_previous, datetime_variable, ...)

Value

A dataframe which contains only rows of df_current that have changes from df_previous, but without new rows. Also returns a waldo object as in loupe().

Arguments

df_current

data.frame, the newest/current version of dataset x.

df_previous

data.frame, the old version of dataset, for example x - t1.

datetime_variable

string, which variable to use as unique ID to join df_current and df_previous. Usually a "datetime" variable.

...

Other waldo::compare() arguments can be supplied here, such as tolerance or max_diffs. See ?waldo::compare() for a full list.

Details

The underlying functionality is handled by create_object_list().

See Also

loupe()

create_object_list()

Examples

# Returning only matched rows which contain changes
df_caught <- butterfly::catch(
  butterflycount$march, # New or current dataset
  butterflycount$february, # Previous version you are comparing it to
  datetime_variable = "time" # Unique ID variable they have in common
)

df_caught