Compare data over time periods

Given a tibble/data.frame, you can get date from two different but comparative date ranges. Lets say you want to compare visits in one year to visits from 2 years before without also seeing the previous 1 year. You can do that with this function.

Usage

ts_compare_data(.data, .date_col, .start_date, .end_date, .periods_back)

Arguments

.data

The date.frame/tibble that holds the data

.date_col

The column with the date value

.start_date

The start of the period you want to analyze

.end_date

The end of the period you want to analyze

.periods_back

How long ago do you want to compare data too. Time units are collapsed using lubridate::floor_date(). The value can be:

• second

• minute

• hour

• day

• week

• month

• bimonth

• quarter

• season

• halfyear

• year

Arbitrary unique English abbreviations as in the lubridate::period() constructor are allowed.

Value

A tibble.

Details

• Uses the timetk::filter_by_time() function in order to filter the date column.

• Uses the timetk::subtract_time() function to subtract time from the start date.

See also

Other Time_Filtering: ts_time_event_analysis_tbl()

Author

Steven P. Sanderson II, MPH

Examples

suppressPackageStartupMessages(library(dplyr))
suppressPackageStartupMessages(library(timetk))

data_tbl <- ts_to_tbl(AirPassengers) %>%
  select(-index)

ts_compare_data(
  .data           = data_tbl
  , .date_col     = date_col
  , .start_date   = "1955-01-01"
  , .end_date     = "1955-12-31"
  , .periods_back = "2 years"
  ) %>%
  summarise_by_time(
    .date_var = date_col
    , .by     = "year"
    , visits  = sum(value)
  )
#> # A tibble: 2 × 2
#>   date_col   visits
#>   <date>      <dbl>
#> 1 1953-01-01   2700
#> 2 1955-01-01   3408