reduce Reduce() for merging lists

use do.call() instead to avoid quadratic complexity of growing lists

Author: alyst

R/subplots.R

@@ -266,7 +266,7 @@ subplot <- function(..., nrows = 1, widths = NULL, heights = NULL, margin = 0.02
   }
 
   p <- list(
-    data = Reduce(c, traces),
+    data = unlist(traces, recursive = FALSE),
     layout = Reduce(modify_list, c(xAxes, rev(yAxes)))
   )
 
@@ -275,9 +275,10 @@ subplot <- function(..., nrows = 1, widths = NULL, heights = NULL, margin = 0.02
   annotations <- Map(reposition, annotations, split(domainInfo, seq_along(plots)))
   shapes <- Map(reposition, shapes, split(domainInfo, seq_along(plots)))
   images <- Map(reposition, images, split(domainInfo, seq_along(plots)))
-  p$layout$annotations <- Reduce(c, annotations)
-  p$layout$shapes <- Reduce(c, shapes)
-  p$layout$images <- Reduce(c, images)
+  p$layout$annotations <- unlist(annotations, recursive = FALSE)
+  p$layout$shapes <- unlist(shapes, recursive = FALSE)
+  p$layout$images <- unlist(images, recursive = FALSE)
+
   # merge non-axis layout stuff
   layouts <- lapply(layouts, function(x) {
     x[!grepl("^[x-y]axis|^geo|^mapbox|annotations|shapes|images", names(x))] %||% list()
@@ -290,8 +291,8 @@ subplot <- function(..., nrows = 1, widths = NULL, heights = NULL, margin = 0.02
     }
     layouts <- layouts[which_layout]
   }
-  p$attrs <- Reduce(c, lapply(plots, "[[", "attrs"))
-  p$layout <- modify_list(p$layout, Reduce(modify_list, layouts))
+  p$attrs <- unlist(lapply(plots, "[[", "attrs"), recursive = FALSE)
+  p$layout <- Reduce(modify_list, layouts, p$layout)
   p$source <- ensure_one(plots, "source")
   p$config <- ensure_one(plots, "config")
   p$highlight <- ensure_one(plots, "highlight")
@@ -399,7 +400,7 @@ get_domains <- function(nplots = 1, nrows = 1, margins = 0.01,
 
 list2df <- function(x, nms) {
   #stopifnot(length(unique(sapply(x, length))) == 1)
-  m <- if (length(x) == 1) t(x[[1]]) else Reduce(rbind, x)
+  m <- if (length(x) == 1) t(x[[1]]) else do.call(rbind, x)
   row.names(m) <- NULL
   df <- data.frame(m)
   if (!missing(nms)) setNames(df, nms) else df