A trendline on a chart series

`xl_chart_trendline()` fits a line through a series.

Two of Excel's own restrictions are enforced, because it discards these rather than complain: a **moving average** has no forecast, no equation and no R-squared, and an **intercept** applies only to exponential, linear and polynomial fits.

Usage

xl_chart_trendline(
  type,
  order = NA,
  period = NA,
  forward = NA,
  backward = NA,
  intercept = NA,
  equation = NA,
  r_squared = NA,
  name = NULL,
  format = NULL
)

Arguments

type

`"linear"`, `"log"`, `"poly"`, `"power"`, `"exp"` or `"average"` for a moving average.

order

The order of a polynomial fit, 2 or more. `"poly"` only.

period

The number of points a moving average covers, 2 or more. `"average"` only.

forward, backward

How far to project the line beyond the data, in categories.

intercept

Force the line through this value on the y axis. Exponential, linear and polynomial fits only.

equation

Print the fitted equation on the chart.

r_squared

Print the R-squared value on the chart.

name

The trendline's name in the legend. Excel generates one otherwise.

format

An [xl_format()] styling the line — [xl_border()] only, since a trendline is a line.

Value

An `xl_chart_trendline` object.

See also

[xl_chart_series]

Other images and charts: xl_chart(), xl_chart_axis(), xl_chart_error_bars(), xl_chart_labels(), xl_chart_legend(), xl_chart_marker(), xl_chart_series(), xl_chart_table(), xl_chartsheet(), xl_image()

Examples

xl_chart_trendline("linear", equation = TRUE, r_squared = TRUE)
#> <xl_chart_trendline>
#>   set: type, equation, r_squared 
xl_chart_trendline("poly", order = 3)
#> <xl_chart_trendline>
#>   set: type, order 
xl_chart_trendline("average", period = 2)
#> <xl_chart_trendline>
#>   set: type, period