blvim (version 0.1.1)

sim_df_extract: Extract or replace parts of a SIM data frame

Description

Extract or replace subsets of SIM data frames. The behaviour of the functions is very close to the one of the corresponding data.frame functions, see [.data.frame. However, modifications of the SIM columns or suppression of core columns will turn the object into a standard data.frame to void issues in e.g. graphical representations, see below for details.

Usage

# S3 method for sim_df
$(x, name) <- value
# S3 method for sim_df
[[(x, i, j) <- value
# S3 method for sim_df
[(x, i, j, ..., drop)
# S3 method for sim_df
[(x, i, j) <- value

Value

For [ a sim_df, a data.frame or a single column depending on the values of i and j.

For [[ a column of the sim_df (or NULL) or an element of a column when two indices are used.

For $ a column of the sim_df (or NULL).

For [<-, [[<-, and $<- a sim_df or a data frame (see details).

Arguments

x

data frame of spatial interaction models, an object of class sim_df

name

a literal character string

value

a suitable replacement value: it will be repeated a whole number of times if necessary and it may be coerced: see the Coercion section in [.data.frame. If NULL, deletes the column if a single column is selected.

i, j, ...

elements to extract or replace. For [ and [[, these are numeric or character or, for [ only, empty or logical. Numeric values are coerced to integer as if by as.integer. For replacement by [, a logical matrix is allowed.

drop

If TRUE the result is coerced to the lowest possible dimension. The default is to drop if only one column is left, but not to drop if only one row is left.

Details

In a sim_df, the core columns are derived from the sim_list column. Replacement functions maintain this property by updating the columns after any modification of the sim_list column. Modifications of the core columns are rejected (removing a core column is accepted but this turns the sim_df into a standard data.frame).

In addition, the sim_list column obeys to restriction on sim_list modifications (i.e, a sim_list contains a homogeneous collection of spatial interaction models).

Extraction functions keep the sim_df class only if the result is a data frame with a sim_list column, the core columns and potentially additional columns.

Examples

distances <- french_cities_distances[1:10, 1:10] / 1000 ## convert to km
production <- rep(1, 10)
attractiveness <- log(french_cities$area[1:10])
all_flows <- grid_blvim(distances, production, seq(1.05, 1.45, by = 0.2),
  seq(1, 3, by = 0.5) / 400,
  attractiveness,
  bipartite = FALSE,
  epsilon = 0.1, iter_max = 1000,
)
all_flows_df <- sim_df(all_flows)
## the models as a sim_list
all_flows_df[, "sim"]
## sub data frame, a sim_df
all_flows_df[1:5, ]
## sub data frame, not a sim_df (alpha is missing)
all_flows_df[6:10, 2:6]
all_flows_2 <- grid_blvim(distances, log(french_cities$population[1:10]),
  seq(1.05, 1.45, by = 0.2),
  seq(1, 3, by = 0.5) / 400,
  attractiveness,
  bipartite = FALSE,
  epsilon = 0.1, iter_max = 1000,
)
## replace the sim_list column by the new models
## before
all_flows_df$diversity
all_flows_df$sim <- all_flows_2
## after (all core columns have been updated)
all_flows_df$diversity