query_list: Data validation queries across a list of data frames
In epicentre-msf/queryr: Data Validation Queries With Tidy Output

View source: R/query_list.R

query_list

R Documentation

Data validation queries across a list of data frames

Description

Find observations matching a query that concerns one or more data frames within a list of data frames, and return tidy, stackable output. Like query but enables query expressions that reference variables in multiple data frames.

If the query expression references variables from data frames (i.e. list elements) other than the focal element, the relevant variable(s) will be joined to the focal element before the query expression is evaluated, see arguments join_type and join_by below.

Usage

query_list(
  x,
  cond,
  element,
  cols_base,
  join_type = "left",
  join_by,
  pivot_long = TRUE,
  pivot_var = "variable",
  pivot_val = "value",
  as_chr = TRUE
)

Arguments

`x`	A list of data frames
`cond`	Expression to evaluate with respect to one or more variables in one or more of the data frames within `x`.
`element`	Name or integer index of the focal list element of `x` for the given query. If the query expression `cond` references variables from list elements apart from `element`, the relevant variable(s) will be joined to `x[[element]]` before the query expression is evaluated, based on the `join_type` and `join_by` arguments described below.
`cols_base`	(Optional) Tidy-selection of other columns within `data` to retain in the output. Can optionally be set for an entire session using option "queryr_cols_base", e.g. `options(queryr_cols_base = quote(id:site))`.
`join_type`	If `cond` references variables within elements of `x` apart from `x[[element]]`, what type of join should be used to join the relevant elements? Options are "left" (the default) and "inner". Based on dplyr `join` types.
`join_by`	A character vector of variables to join by. If the join key columns have different names in `x[[element]]` and `x[[other]]`, use a named vector. For example, `join_by = c("a" = "b")` will match `x[[element]]$a` to `x[[other]]$b`.
`pivot_long`	Logical indicating whether to pivot the variables referenced within `cond` to a long (i.e. stackable) format, with default column names "variable1", "value1", "variable2", "value2", ... Defaults to `TRUE`.
`pivot_var`	Prefix for pivoted variable column(s). Defaults to "variable". Only used if `pivot_long = TRUE`.
`pivot_val`	Prefix for pivoted value column(s). Defaults to "value". Only used if `pivot_long = TRUE`.
`as_chr`	Logical indicating whether to coerce the columns referenced in the query expression `cond` to character prior to returning. This enables row-binding multiple queries with variables of different classes, but is only important if `pivot_long = TRUE`. Defaults to `TRUE`.