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#' Make a rename columns node (copies columns not renamed).
#'
#' @param source source to rename from.
#' @param cmap map written as new column names as keys and old column names as values.
#' @param env environment to look to.
#' @return rename columns node.
#'
#' @examples
#'
#' if (requireNamespace("DBI", quietly = TRUE) && requireNamespace("RSQLite", quietly = TRUE)) {
#' my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
#' d <- rq_copy_to(my_db, 'd',
#' data.frame(AUC = 0.6, R2 = 0.2, z = 3))
#' op_tree <- rename_columns(d, c('R2' %:=% 'AUC', 'AUC' %:=% 'R2'))
#' cat(format(op_tree))
#' sql <- to_sql(op_tree, my_db)
#' cat(sql)
#' print(DBI::dbGetQuery(my_db, sql))
#' DBI::dbDisconnect(my_db)
#' }
#'
#' @export
#'
rename_columns <- function(source, cmap,
env = parent.frame()) {
force(env)
UseMethod("rename_columns", source)
}
#' @export
rename_columns.relop <- function(source, cmap,
env = parent.frame()) {
force(env)
if(length(cmap)<=0) {
return(source)
}
if(length(cmap)!=length(unique(as.character(cmap)))) {
stop("rquery::rename_columns map values must be unique")
}
if(length(cmap)!=length(unique(names(cmap)))) {
stop("rquery::rename_columns map keys must be unique")
}
have <- column_names(source)
check_have_cols(have, as.character(cmap),
"rquery::rename_columns cmap")
collisions <- intersect(names(cmap),
setdiff(have, as.character(cmap)))
if(length(collisions)>0) {
stop(paste("rquery::rename_columns rename collisions",
paste(collisions, collapse = ", ")))
}
cmap <- cmap[names(cmap)!=cmap]
if(length(cmap)<=0) {
return(source)
}
r <- list(source = list(source),
table_name = NULL,
parsed = NULL,
cmap = cmap)
r <- relop_decorate("relop_rename_columns", r)
r
}
#' @export
rename_columns.data.frame <- function(source, cmap,
env = parent.frame()) {
force(env)
if(length(cmap)<=0) {
stop("rquery::rename_columns must rename at least 1 column")
}
if(length(cmap)!=length(unique(as.character(cmap)))) {
stop("rquery::rename_columns map values must be unique")
}
if(length(cmap)!=length(unique(names(cmap)))) {
stop("rquery::rename_columns map keys must be unique")
}
tmp_name <- mk_tmp_name_source("rquery_tmp")()
dnode <- mk_td(tmp_name, colnames(source))
enode <- rename_columns(dnode, cmap, env = env)
rquery_apply_to_data_frame(source, enode, env = env)
}
#' @export
column_names.relop_rename_columns <- function (x, ...) {
wrapr::stop_if_dot_args(substitute(list(...)),
"rquery::column_names.relop_rename_columns")
sc <- column_names(x$source[[1]])
rmap <- names(x$cmap)
names(rmap) <- as.character(x$cmap)
sc[sc %in% names(rmap)] <- rmap[sc[sc %in% names(rmap)]]
sc
}
#' @export
format_node.relop_rename_columns <- function(node) {
paste0("rename_columns(.,\n",
" ", gsub("\n", "\n ",
wrapr::map_to_char(node$cmap, sep = "\n "),
fixed = TRUE), ")",
"\n")
}
calc_used_relop_rename_columns <- function (x,
...,
using = NULL) {
wrapr::stop_if_dot_args(substitute(list(...)),
"rquery:::calc_used_relop_rename_columns")
cols <- column_names(x)
if(length(using)>0) {
missing <- setdiff(using, cols)
if(length(missing)>0) {
stop(paste("rquery::calc_used_relop_rename_columns unknown columns",
paste(missing, collapse = ", ")))
}
cols <- intersect(cols, using)
}
# map back prior to rename
rmap <- x$cmap
sc <- cols
sc[sc %in% names(rmap)] <- rmap[sc[sc %in% names(rmap)]]
names(sc) <- cols
sc
}
#' @export
columns_used.relop_rename_columns <- function (x,
...,
using = NULL) {
wrapr::stop_if_dot_args(substitute(list(...)),
"rquery::columns_used.relop_rename_columns")
qmap <- calc_used_relop_rename_columns(x, using=using)
return(columns_used(x$source[[1]],
using = as.character(qmap)))
}
#' @export
to_sql.relop_rename_columns <- function (x,
db,
...,
limit = NULL,
source_limit = NULL,
indent_level = 0,
tnum = mk_tmp_name_source('tsql'),
append_cr = TRUE,
using = NULL) {
wrapr::stop_if_dot_args(substitute(list(...)), "rquery::to_sql.relop_rename_columns")
dispatch_to_sql_method(
method_name = "to_sql.relop_rename_columns",
x = x,
db = db,
limit = limit,
source_limit = source_limit,
indent_level = indent_level,
tnum = tnum,
append_cr = append_cr,
using = using)
}
to_sql_relop_rename_columns <- function(
x,
db,
...,
limit = NULL,
source_limit = NULL,
indent_level = 0,
tnum = mk_tmp_name_source('tsql'),
append_cr = TRUE,
using = NULL) {
wrapr::stop_if_dot_args(substitute(list(...)),
"rquery::to_sql.relop_rename_columns")
qmap <- calc_used_relop_rename_columns(x, using=using)
colsV <- vapply(as.character(qmap),
function(ci) {
quote_identifier(db, ci)
}, character(1))
colsA <- vapply(names(qmap),
function(ci) {
quote_identifier(db, ci)
}, character(1))
cols <- paste(colsV, "AS", colsA)
subsql_list <- to_sql(x$source[[1]],
db = db,
limit = limit,
source_limit = source_limit,
indent_level = indent_level + 1,
tnum = tnum,
append_cr = FALSE,
using = as.character(qmap))
subsql <- subsql_list[[length(subsql_list)]]
tab <- tnum()
prefix <- paste(rep(' ', indent_level), collapse = '')
q <- paste0(prefix, "SELECT\n",
prefix, " ", paste(cols, collapse = paste0(",\n", prefix, " ")), "\n",
prefix, "FROM (\n",
subsql, "\n",
prefix, ") ",
tab)
if(!is.null(limit)) {
q <- paste(q, "LIMIT",
format(ceiling(limit), scientific = FALSE))
}
if(append_cr) {
q <- paste0(q, "\n")
}
c(subsql_list[-length(subsql_list)], q)
}
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