Uses if_else_block.

assign_slice(source, testexpr, columns, value, env = parent.frame())

Arguments

source

optree relop node or data.frame.

testexpr

character containing the test expression.

columns

character vector of column names to alter.

value

value to set in matching rows and columns (scalar).

env

environment to look to.

Value

optree or data.frame.

Details

Note: ifebtest_* is a reserved column name for this procedure.

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(i = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10), a = c(0, 0, 1, 1, 1, 1, 1, 1, 1, 1), b = c(0, 1, 0, 1, 1, 1, 1, 1, 1, 1), r = runif(10)), temporary=TRUE, overwrite=TRUE) optree <- d %.>% assign_slice(., testexpr = qe(r<0.5), columns = qc(a, b), value = 2) cat(format(optree)) sql <- to_sql(optree, my_db) cat(sql) print(DBI::dbGetQuery(my_db, sql)) DBI::dbDisconnect(my_db) }
#> table(`d`; #> i, #> a, #> b, #> r) %.>% #> extend(., #> ifebtest_1 := r < 0.5) %.>% #> extend(., #> a := ifelse(ifebtest_1, 2, a), #> b := ifelse(ifebtest_1, 2, b)) %.>% #> drop_columns(., #> ifebtest_1) #> SELECT #> `i`, #> `a`, #> `b`, #> `r` #> FROM ( #> SELECT #> `i`, #> `r`, #> ( CASE WHEN ( `ifebtest_1` ) THEN ( 2 ) WHEN NOT ( `ifebtest_1` ) THEN ( `a` ) ELSE NULL END ) AS `a`, #> ( CASE WHEN ( `ifebtest_1` ) THEN ( 2 ) WHEN NOT ( `ifebtest_1` ) THEN ( `b` ) ELSE NULL END ) AS `b` #> FROM ( #> SELECT #> `i`, #> `a`, #> `b`, #> `r`, #> `r` < 0.5 AS `ifebtest_1` #> FROM ( #> SELECT #> `i`, #> `a`, #> `b`, #> `r` #> FROM #> `d` #> ) tsql_92351842149327380637_0000000000 #> ) tsql_92351842149327380637_0000000001 #> ) tsql_92351842149327380637_0000000002 #> i a b r #> 1 1 2 2 0.40797320 #> 2 2 2 2 0.35124881 #> 3 3 1 0 0.73809156 #> 4 4 1 1 0.66428549 #> 5 5 2 2 0.08522470 #> 6 6 1 1 0.85613216 #> 7 7 2 2 0.07698332 #> 8 8 1 1 0.85284480 #> 9 9 2 2 0.10634696 #> 10 10 2 2 0.48480282