stplanr (version 0.6.0)

od_id: Combine two ID values to create a single ID number

Description

Combine two ID values to create a single ID number

Usage

od_id_szudzik(x, y, ordermatters = FALSE)
od_id_max_min(x, y)
od_id_character(x, y)

Arguments

x

a vector of numeric, character, or factor values

y

a vector of numeric, character, or factor values

ordermatters

logical, does the order of values matter to pairing, default = FALSE

Details

In OD data it is common to have many 'oneway' flows from "A to B" and "B to A". It can be useful to group these an have a single ID that represents pairs of IDs with or without directionality, so they contain 'twoway' or bi-directional values.

od_id* functions take two vectors of equal length and return a vector of IDs, which are unique for each combination but the same for twoway flows.

• the Szudzik pairing function, on two vectors of equal length. It returns a vector of ID numbers.

This function superseeds od_id_order as it is faster on large datasets

See Also

od_oneway

Other od: dist_google(), od2line(), od2odf(), od_aggregate_from(), od_aggregate_to(), od_aggregate(), od_coords2line(), od_coords(), od_dist(), od_oneway(), od_radiation(), od_to_odmatrix(), odmatrix_to_od(), points2flow(), points2odf(), sp_aggregate()

Examples

# NOT RUN {
(d <- od_data_sample[2:9, 1:2])
(id <- od_id_character(d[[1]], d[[2]]))
duplicated(id)
od_id_szudzik(d[[1]], d[[2]])
od_id_max_min(d[[1]], d[[2]])
n <- 100
ids <- as.character(runif(n, 1e4, 1e7 - 1))
# benchmark of methods:
x <- data.frame(
  id1 = rep(ids, times = n),
  id2 = rep(ids, each = n),
  val = 1,
  stringsAsFactors = FALSE
)
bench::mark(check = FALSE, iterations = 10,
  od_id_order(x),
  od_id_character(x$id1, x$id2),
  od_id_szudzik(x$id1, x$id2),
  od_id_max_min(x$id1, x$id2)
)
# }