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Check whether a .vtr column has a usable hash index

Source: R/index.R
has_index.Rd

TRUE when the .vtri sidecar is present, readable, in the current format, and built against the store as it now stands. An index that no longer matches the store, or that cannot be read, reads as FALSE, because queries ignore it and fall back to a scan; create_index() rebuilds it.

Usage

has_index(path, column)

Arguments

path

Path to a .vtr file.

column

Character vector. Name(s) of column(s), in any order.

Value

Logical scalar: TRUE if the index exists and can be used.

Examples

f <- tempfile(fileext = ".vtr")
write_vtr(data.frame(id = letters, val = 1:26, stringsAsFactors = FALSE), f)
has_index(f, "id")   # FALSE
create_index(f, "id")
has_index(f, "id")   # TRUE
unlink(c(f, paste0(f, ".id.vtri")))