smap: Map Functions Over Glycan Structure Vectors

In glyrepr: Representation for Glycan Compositions and Structures

Map Functions Over Glycan Structure Vectors

Description

These functions apply a function to each unique structure in a glycan structure vector, taking advantage of hash-based deduplication to avoid redundant computation. Similar to purrr mapping functions, but optimized for glycan structure vectors.

Usage

smap(.x, .f, ...)

smap_vec(.x, .f, ..., .ptype = NULL)

smap_lgl(.x, .f, ...)

smap_int(.x, .f, ...)

smap_dbl(.x, .f, ...)

smap_chr(.x, .f, ...)

smap_structure(.x, .f, ...)

Arguments

.x	A glycan structure vector (glyrepr_structure).
.f	A function that takes an igraph object and returns a result. Can be a function, purrr-style lambda (~ .x$attr), or a character string naming a function. A structure with floating metadata is passed as one annotated graph, including its floating_parts and/or floating_substituents graph attributes.
...	Additional arguments passed to .f.
.ptype	A prototype for the return type (for smap_vec).

Details

These functions only compute .f once for each unique structure, then map the results back to the original vector positions. This is much more efficient than applying .f to each element individually when there are duplicate structures.

Structure-returning variants reuse unchanged graphs and validate and canonicalize changed graphs returned by .f. A callback that changes vertex identities or components of a floating structure must also update its floating_parts and floating_substituents metadata.

Return Types:

• smap(): Returns a list with the same length as .x

• smap_vec(): Returns an atomic vector with the same length as .x

• smap_lgl(): Returns a logical vector

• smap_int(): Returns an integer vector

• smap_dbl(): Returns a double vector

• smap_chr(): Returns a character vector

• smap_structure(): Returns a new glycan structure vector (.f must return igraph objects)

Value

• smap(): A list

• smap_vec(): An atomic vector of type specified by .ptype

• smap_lgl/int/dbl/chr(): Atomic vectors of the corresponding type

• smap_structure(): A new glyrepr_structure object

Examples

# Create a structure vector with duplicates
core1 <- o_glycan_core_1()
core2 <- n_glycan_core()
structures <- c(core1, core2, core1)  # core1 appears twice

# Map a function that counts vertices - only computed twice, not three times
smap_int(structures, igraph::vcount)

# Map a function that returns logical
smap_lgl(structures, function(g) igraph::vcount(g) > 5)

# Use purrr-style lambda functions
smap_int(structures, ~ igraph::vcount(.x))
smap_lgl(structures, ~ igraph::vcount(.x) > 5)

# Map a function that modifies structure (must return igraph)
add_vertex_names <- function(g) {
  if (!("name" %in% igraph::vertex_attr_names(g))) {
    igraph::set_vertex_attr(g, "name", value = paste0("v", seq_len(igraph::vcount(g))))
  } else {
    g
  }
}
smap_structure(structures, add_vertex_names)

glyrepr documentation built on Sept. 22, 2026, 5:09 p.m.