peek_point: Peek First Interval Matching a Point

In Immutables: Fast and Functional Data Structures

Peek First Interval Matching a Point

Description

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.

Details

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

Value

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

Examples

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

# 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
peek_point(edge, 3, bounds = "[]") # closed bounds: endpoint matches

# Coordinate-equality modes (bounds irrelevant)
peek_point(ix, 2, match_at = "start")  # entry starting at 2
peek_point(ix, 3, match_at = "end")    # entry ending at 3

Immutables documentation built on April 29, 2026, 1:06 a.m.