ggplot2 x-axis label formatter for time-of-day plots.

Returns a labeller function that formats POSIXct values as readable hour strings (e.g. "6 am", "2 pm"). Designed for use with ggplot2::scale_x_datetime after converting your time column with commontime.

Usage

label_hour(tz = Sys.timezone())

Arguments

tz

Time zone string (e.g. 'America/New_York'). Defaults to your system time zone. Should match the tz argument passed to commontime.

Value

A function that accepts a POSIXct vector and returns a character vector of hour labels.

Details

Time zone tip: use the same tz here as you passed to commontime so that the axis labels match your data.

See also

commontime to prepare your time column, theme_buzzr for a matching plot theme.

Examples

# Typical usage with ggplot2 (not run):
# ggplot(df, aes(x = commontime(bin_datetime, tz = 'America/New_York'),
#               y = detectionrate_ins_buzz, color = flower)) +
#   geom_line() +
#   scale_x_datetime(labels = label_hour(tz = 'America/New_York')) +
#   theme_buzzr()

# The labeller itself:
fmt <- label_hour(tz = 'America/New_York')
fmt(as.POSIXct('2000-01-01 08:00:00', tz = 'America/New_York'))  # "8 am"
#> [1] "8 am"
fmt(as.POSIXct('2000-01-01 14:00:00', tz = 'America/New_York'))  # "2 pm"
#> [1] "2 pm"