pointblank (version 0.6.0)

yaml_read_agent: Read a pointblank YAML file to create an agent object

Description

With yaml_read_agent() we can read a pointblank YAML file that describes a validation plan to be carried out by an agent (typically generated by the yaml_write() function. What's returned is a new agent with that validation plan, ready to interrogate the target table at will (using the table-reading function stored as the read_fn). The agent can be given more validation steps if needed before using interrogate() or taking part in any other agent ops (e.g., writing to disk with outputs intact via x_write_disk() or again to pointblank YAML with yaml_write()).

To get a picture of how yaml_read_agent() is interpreting the validation plan specified in the pointblank YAML, we can use the yaml_agent_show_exprs() function. That function shows us (in the console) the pointblank expressions for generating the described validation plan.

Usage

yaml_read_agent(path)

Arguments

path

A path to a pointblank YAML file that contains fields related to an agent.

Function ID

9-2

See Also

Other pointblank YAML: yaml_agent_interrogate(), yaml_agent_show_exprs(), yaml_agent_string(), yaml_informant_incorporate(), yaml_read_informant(), yaml_write()

Examples

# NOT RUN {
# Let's go through the process of
# developing an agent with a validation
# plan (to be used for the data quality
# analysis of the `small_table` dataset),
# and then offloading that validation
# plan to a pointblank YAML file; this
# will be read in with `yaml_read_agent()`

# We ought to think about what's
# tolerable in terms of data quality so
# let's designate proportional failure
# thresholds to the `warn`, `stop`, and
# `notify` states using `action_levels()`
al <- 
  action_levels(
    warn_at = 0.10,
    stop_at = 0.25,
    notify_at = 0.35
  )

# Now create a pointblank `agent` object
# and give it the `al` object (which
# serves as a default for all validation
# steps which can be overridden); the
# data will be referenced in a `read_fn`
# (a requirement for writing to YAML)
agent <- 
  create_agent(
    read_fn = ~small_table,
    label = "A simple example with the `small_table`.",
    actions = al
  )

# Then, as with any `agent` object, we
# can add steps to the validation plan by
# using as many validation functions as we
# want
agent <-
  agent %>% 
  col_exists(vars(date, date_time)) %>%
  col_vals_regex(
    vars(b), "[0-9]-[a-z]{3}-[0-9]{3}"
  ) %>%
  rows_distinct() %>%
  col_vals_gt(vars(d), 100) %>%
  col_vals_lte(vars(c), 5)

# The agent can be written to a pointblank
# YAML file with `yaml_write()`
# yaml_write(
#   agent = agent,
#   filename = "agent-small_table.yml"
# )

# The 'agent-small_table.yml' file is
# available in the package through `system.file()`
yml_file <- 
  system.file(
    "agent-small_table.yml",
    package = "pointblank"
  )

# We can view the YAML file in the console
# with the `yaml_agent_string()` function
yaml_agent_string(path = yml_file)

# The YAML can also be printed in the console
# by supplying the agent as the input
yaml_agent_string(agent = agent)

# At a later time, the YAML file can
# be read into a new agent with the
# `yaml_read_agent()` function
agent <- yaml_read_agent(path = yml_file)

class(agent)

# We can interrogate the data (which
# is accessible through the `read_fn`)
# with `interrogate()` and get an
# agent with intel, or, we can
# interrogate directly from the YAML
# file with `yaml_agent_interrogate()`
agent <- 
  yaml_agent_interrogate(path = yml_file)

class(agent)

# }