Peek First Interval Matching a Point

Usage

peek_point(
  x,
  point,
  bounds = NULL,
  match_at = c("interval", "start", "end", "either")
)

Arguments

x: An interval_index.
point: Query point.
bounds: Optional boundary override. One of "[)", "[]", "()", "(]". Ignored when match_at is not "interval".
match_at: How the query point is matched against each entry. One of "interval" (default; entry interval contains point, under bounds), "start" (entry's start coordinate equals point), "end" (entry's end equals point), or "either" (start or end equals point). The three coordinate-equality modes are structural and ignore bounds.

Value

The payload value from the first match, or NULL on no match.

Details

Returns the first match in canonical interval order. Use peek_all_point() to retrieve all matches as an interval_index slice.

Examples

ix <- interval_index("a", "b", "c", start = c(1, 2, 4), end = c(3, 2, 5))
peek_point(ix, 2)
#> [1] "a"

# Boundary override at an endpoint
edge <- interval_index("a", start = 1, end = 3, default_query_bounds = "[)")
peek_point(edge, 3)                # default "[)": no match at right endpoint
#> NULL
peek_point(edge, 3, bounds = "[]") # closed bounds: endpoint matches
#> [1] "a"

# Coordinate-equality modes (bounds irrelevant)
peek_point(ix, 2, match_at = "start")  # entry starting at 2
#> [1] "b"
peek_point(ix, 3, match_at = "end")    # entry ending at 3
#> [1] "a"