Class: RuboCop::Cop::Performance::Sample

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/performance/sample.rb

Overview

This cop is used to identify usages of shuffle.first, shuffle.last and shuffle[] and change them to use sample instead.

Examples:

# bad
[1, 2, 3].shuffle.first
[1, 2, 3].shuffle.first(2)
[1, 2, 3].shuffle.last
[1, 2, 3].shuffle[2]
[1, 2, 3].shuffle[0, 2]    # sample(2) will do the same
[1, 2, 3].shuffle[0..2]    # sample(3) will do the same
[1, 2, 3].shuffle(random: Random.new).first

# good
[1, 2, 3].shuffle
[1, 2, 3].sample
[1, 2, 3].sample(3)
[1, 2, 3].shuffle[1, 3]    # sample(3) might return a longer Array
[1, 2, 3].shuffle[1..3]    # sample(3) might return a longer Array
[1, 2, 3].shuffle[foo, bar]
[1, 2, 3].shuffle(random: Random.new)

Defined Under Namespace

Classes: ShuffleAnalyzer

Constant Summary collapse

MSG =
'Use `%<correct>s` instead of `%<incorrect>s`.'

Constants included from Util

Util::ASGN_NODES, Util::BASIC_LITERALS, Util::EQUALS_ASGN_NODES, Util::LITERALS, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #correct, #debug?, #details, #display_cop_names?, #display_style_guide?, #excluded_file?, #extra_details?, inherited, #initialize, #join_force?, lint?, match?, #message, non_rails, qualified_cop_name, rails?, #reference_url, #relevant_file?, #style_guide_url

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, directions, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, move_pos, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

hidden?, issue_deprecation_warning, match_path?, relative_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#autocorrect(node) ⇒ Object


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# File 'lib/rubocop/cop/performance/sample.rb', line 36

def autocorrect(node)
  ShuffleAnalyzer.new(node).autocorrect
end

#on_send(node) ⇒ Object


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# File 'lib/rubocop/cop/performance/sample.rb', line 30

def on_send(node)
  analyzer = ShuffleAnalyzer.new(node)
  return unless analyzer.offensive?
  add_offense(node, analyzer.source_range, analyzer.message)
end