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Implement appearance order for vec_locate_sorted_groups() #1747

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Implement appearance order for vec_locate_sorted_groups() #1747

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Implement `appearance` order for `vec_locate_sorted_groups()`
DavisVaughan Nov 16, 2022
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DavisVaughan Nov 16, 2022
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5 changes: 5 additions & 0 deletions NEWS.md
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Original file line number Diff line number Diff line change
@@ -1,5 +1,10 @@
# vctrs (development version)

* `vec_locate_sorted_groups()` has gained an `appearance` argument to optionally
return group keys in the order of their first appearance. This makes
`vec_locate_sorted_groups()` almost identical to `vec_group_loc()`, but they
are implemented with very different algorithms (#1747).

# vctrs 0.5.1

* Fix for CRAN checks.
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37 changes: 29 additions & 8 deletions R/order.R
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Original file line number Diff line number Diff line change
Expand Up @@ -185,8 +185,15 @@ vec_sort_radix <- function(x,
#'
#' `vec_locate_sorted_groups()` returns a data frame containing a `key` column
#' with sorted unique groups, and a `loc` column with the locations of each
#' group in `x`. It is similar to [vec_group_loc()], except the groups are
#' returned sorted rather than by first appearance.
#' group in `x`.
#'
#' `vec_locate_sorted_groups()` is very similar to [vec_group_loc()], except
#' the groups are typically sorted by value rather than by first appearance.
#' If `appearance = TRUE`, then the two functions are roughly identical, with
#' the main difference being that `vec_locate_sorted_groups(appearance = TRUE)`
#' computes the groups using a sort-based approach, and `vec_group_loc()`
#' computes them using a hash-based approach. One may be faster than the other
#' depending on the structure of the input data.
#'
#' @details
#' `vec_locate_sorted_groups(x)` is equivalent to, but faster than:
Expand All @@ -198,6 +205,14 @@ vec_sort_radix <- function(x,
#'
#' @inheritParams order-radix
#'
#' @param appearance Ordering of returned group keys.
#'
#' If `FALSE`, the default, group keys are returned sorted by value.
#'
#' If `TRUE`, group keys are returned sorted by first appearance in `x`. This
#' means `direction`, `na_value`, and `chr_proxy_collate` no longer have any
#' effect.
#'
#' @return
#' A two column data frame with size equal to `vec_size(vec_unique(x))`.
#' * A `key` column of type `vec_ptype(x)`.
Expand All @@ -215,16 +230,21 @@ vec_sort_radix <- function(x,
#' )
#'
#' # `vec_locate_sorted_groups()` is similar to `vec_group_loc()`, except keys
#' # are returned ordered rather than by first appearance.
#' # are returned ordered rather than by first appearance by default.
#' vec_locate_sorted_groups(df)
#'
#' vec_group_loc(df)
#'
#' # Setting `appearance = TRUE` makes `vec_locate_sorted_groups()` mostly
#' # equivalent to `vec_group_loc()`, but their underlying algorithms are very
#' # different.
#' vec_locate_sorted_groups(df, appearance = TRUE)
vec_locate_sorted_groups <- function(x,
...,
direction = "asc",
na_value = "largest",
nan_distinct = FALSE,
chr_proxy_collate = NULL) {
chr_proxy_collate = NULL,
appearance = FALSE) {
check_dots_empty0(...)

.Call(
Expand All @@ -233,7 +253,8 @@ vec_locate_sorted_groups <- function(x,
direction,
na_value,
nan_distinct,
chr_proxy_collate
chr_proxy_collate,
appearance
)
}

Expand All @@ -245,9 +266,9 @@ vec_order_info <- function(x,
na_value = "largest",
nan_distinct = FALSE,
chr_proxy_collate = NULL,
chr_ordered = TRUE) {
appearance = FALSE) {
Comment on lines -248 to +269
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As you'll see in the C code, appearance = TRUE has become the "official" way of saying that we don't need to actually order character vectors, we just need to group them, allowing us to use the faster chr_appearance() C function vs using chr_order(). It has replaced the chr_ordered argument that was being used for testing.

This is the first time we would be exposing chr_appearance() to user code. I added and tested it a while back with the eventual goal of exposing it as an optimization somehow, and I like how it happens here through appearance.

check_dots_empty0(...)
.Call(vctrs_order_info, x, direction, na_value, nan_distinct, chr_proxy_collate, chr_ordered)
.Call(vctrs_order_info, x, direction, na_value, nan_distinct, chr_proxy_collate, appearance)
}

# ------------------------------------------------------------------------------
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30 changes: 25 additions & 5 deletions man/vec_locate_sorted_groups.Rd
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4 changes: 2 additions & 2 deletions src/init.c
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Expand Up @@ -128,7 +128,7 @@ extern SEXP vctrs_locate_complete(SEXP);
extern SEXP vctrs_detect_complete(SEXP);
extern SEXP vctrs_normalize_encoding(SEXP);
extern SEXP vctrs_order(SEXP, SEXP, SEXP, SEXP, SEXP);
extern SEXP vctrs_locate_sorted_groups(SEXP, SEXP, SEXP, SEXP, SEXP);
extern SEXP vctrs_locate_sorted_groups(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
extern SEXP vctrs_order_info(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
extern r_obj* ffi_vec_unrep(r_obj*);
extern SEXP vctrs_fill_missing(SEXP, SEXP, SEXP);
Expand Down Expand Up @@ -303,7 +303,7 @@ static const R_CallMethodDef CallEntries[] = {
{"vctrs_detect_complete", (DL_FUNC) &vctrs_detect_complete, 1},
{"vctrs_normalize_encoding", (DL_FUNC) &vctrs_normalize_encoding, 1},
{"vctrs_order", (DL_FUNC) &vctrs_order, 5},
{"vctrs_locate_sorted_groups", (DL_FUNC) &vctrs_locate_sorted_groups, 5},
{"vctrs_locate_sorted_groups", (DL_FUNC) &vctrs_locate_sorted_groups, 6},
{"vctrs_order_info", (DL_FUNC) &vctrs_order_info, 6},
{"ffi_vec_unrep", (DL_FUNC) &ffi_vec_unrep, 1},
{"vctrs_fill_missing", (DL_FUNC) &vctrs_fill_missing, 3},
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4 changes: 2 additions & 2 deletions src/match-joint.c
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Expand Up @@ -115,7 +115,7 @@ r_obj* vec_joint_xtfrm(r_obj* x,
chrs_smallest,
nan_distinct,
r_null,
true
false
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All these true->false flips are me going from chr_ordered to appearance in the function signatures, which are inverses of one another

), &n_prot);

r_obj* y_info = KEEP_N(vec_order_info(
Expand All @@ -124,7 +124,7 @@ r_obj* vec_joint_xtfrm(r_obj* x,
chrs_smallest,
nan_distinct,
r_null,
true
false
), &n_prot);

const int* v_x_o = r_int_cbegin(r_list_get(x_info, 0));
Expand Down
4 changes: 2 additions & 2 deletions src/match.c
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Expand Up @@ -2012,7 +2012,7 @@ r_obj* compute_nesting_container_info(r_obj* haystack,
chrs_smallest,
true,
r_null,
true
false
), &n_prot);

r_obj* o_haystack = r_list_get(info, 0);
Expand Down Expand Up @@ -2074,7 +2074,7 @@ r_obj* compute_nesting_container_info(r_obj* haystack,
chrs_smallest,
true,
r_null,
true
false
);
r_obj* outer_group_sizes = KEEP_N(r_list_get(info, 1), &n_prot);
v_outer_group_sizes = r_int_cbegin(outer_group_sizes);
Expand Down
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