Class: FlatKit::Command::Stats

Inherits:
FlatKit::Command show all
Defined in:
lib/flat_kit/command/stats.rb

Overview

Internal: The implementation of the stats command.

Instance Attribute Summary

Attributes inherited from FlatKit::Command

#argv, #env, #logger, #opts, #readers, #writer

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from FlatKit::Command

for, #initialize, names

Methods included from DescendantTracker

#children, #find_child, #find_children, #inherited

Constructor Details

This class inherits a constructor from FlatKit::Command

Class Method Details

.description ⇒ Object 



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# File 'lib/flat_kit/command/stats.rb', line 12

def self.description
  "Collect and report stats on the inputfile"
end

.name ⇒ Object 



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# File 'lib/flat_kit/command/stats.rb', line 8

def self.name
  "stats"
end

.parser ⇒ Object 



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# File 'lib/flat_kit/command/stats.rb', line 16

def self.parser
  ::Optimist::Parser.new do
    banner Sort.description.to_s
    banner ""

    banner <<~BANNER
      Given an input file collect basic statistics.

      The statistics can vary based upon the datatype of the field.

      Numeric fields will report the basic count, min, max, mean, standard deviation and sum.
      Non-numeric fields that are comparable, like dates, will report count, min and max.
      Other non-numeric fields will only report the count.

      Adding --cardinality will report the count, and frequency of distinct values in the result.
      This will allow for reporting the median value.

      The fields upon which stats are collected may be selected with the --fields parameter.
      By default statistics are collected on all fields.

      The flatfile type(s) will be automatically determined by the file name.

      The output can be dumped as a CSV, JSON or a a formated ascii table.

    BANNER

    banner <<~USAGE

      Usage:
        fk stats --everything file.json
        fk stats --select surname,given_name file.csv
        fk stats --select surname,given_name --output-format json file.csv > stats.json
        fk stats --select field1,field2 --output-format json input.csv
        fk stats --select field1 file.json.gz -o stats.csv
        gunzip -c file.json.gz | fk stats --input-format json --output-format text

    USAGE

    banner <<~OPTIONS

      Options:

    OPTIONS

    opt :output, "Send the output to the given path instead of standard out.", default: "<stdout>"
    opt :input_format, "Input format, csv or json", default: "auto", short: :none
    opt :output_format, "Output format, csv or json", default: "auto", short: :none
    opt :select, "The comma separted list of field(s) to report stats on", required: false, type: :string
    opt :everything, "Show all statistics that are possible", default: false
    opt :cardinality, "Show the cardinality of the fields, this requires additional memory", default: false
  end
end

Instance Method Details

#call ⇒ Object 



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# File 'lib/flat_kit/command/stats.rb', line 91

def call
  @stats.call
end

#parse ⇒ Object 



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# File 'lib/flat_kit/command/stats.rb', line 69

def parse
  parser = self.class.parser
  ::Optimist.with_standard_exception_handling(parser) do
    opts = parser.parse(argv)
    fields = ::FlatKit::Stats::AllFields
    fields = CSV.parse_line(opts[:select]) if opts[:select]

    stats = [FieldStats::CORE_STATS]
    stats << FieldStats::CARDINALITY_STATS if opts[:cardinality] || opts[:everything]

    paths = parser.leftovers
    raise ::Optimist::CommandlineError, "1 and only 1 input file is allowed" if paths.size > 1

    path = paths.first || "-" # default to stdin
    @stats = ::FlatKit::Stats.new(input: path, input_fallback: opts[:input_format],
                                  output: opts[:output], output_fallback: opts[:output_format],
                                  fields_to_stat: fields, stats_to_collect: stats)
  rescue ::FlatKit::Error => e
    raise ::Optimist::CommandlineError, e.message
  end
end