Ruby skills verification

ruby_verification.md

Be prepared to explain and effectively use following language and ActiveSupport features

Max score: 152

Minimum requirements:

• Independent: 100 (+ all blue diamonds)
• Mid: 120 (+ all orange diamonds)
• Senior: 135 (+ all red triangles)

You will not get a pass if you check more than 5 items that you will not be able to prove being knowledgeable about during verification, so check items only if you are sure about them. Be advised, that questions will be rather general ("what does that return?", "what does it do?", "how does that differ from x?").

Ruby core and std-lib

• Array / Enumerable
  • <<, push, pop 🔹
  • |, &, +
  • at, [], values_at
  • any?, all?, one?, none?
  • map, map!, collect, collect! 🔹
  • count, size, length 🔹
  • cycle
  • delete, delete_at, delete_if
  • drop, drop_while
  • each, each_index, each_with_index 🔹
  • each_cons
  • each_with_object, inject, reduce 🔸
  • empty?
  • index, find_index, rindex
  • first, second, last
  • find, detect 🔹
  • keep_if, select, select!, find_all 🔹
  • flatten, flatten!
  • flat_map
  • group_by
  • include?
  • insert
  • join
  • keep_if, select, select!
  • min, max 🔹
  • min_by, max_by, minmax, minmax_by
  • partition 🔸
  • reject, reject! 🔹
  • reverse, reverse!, reverse_each
  • rotate, rotate! 🔸
  • shift, unshift
  • shuffle, shuffle!
  • sort, sort!, sort_by
  • take_while
  • transpose 🔸
  • uniq, uniq! 🔹
  • zip
• Numeric, Float
  • %, modulo
  • abs
  • ceil, floor
  • div
  • nonzero?
  • round 🔹
  • zero? 🔹
  • positive?, negative?
  • 1/0.0 vs 1/0 🔸
• Object
  • clone, dup
  • enum_for
  • extend
  • is_a?, instance_of?, kind_of?
  • instance_variable_get, instance_variable_set, instance_variable_defined?
  • method
  • nil?
  • send, public_send 🔸
  • respond_to?
  • tap 🔹
  • method_missing 🔺
  • instance_eval, instance_exec 🔺
• String
  • <<
  • =~
  • %
  • +, *
  • []=
  • [], slice
  • capitalize, capitalize!
  • chars
  • chop, chomp
  • count, size
  • delete
  • downcase, downcase!, upcase, upcase!
  • each_char, each_line
  • empty?
  • gsub, gsub!, sub, sub! 🔹
  • include?
  • index
  • ljust, rjust
  • match
  • next, next!, succ, succ!
  • replace
  • reverse, reverse!
  • partition
  • scan
  • split
  • strip, strip!
  • squeeze, squeeze!
  • start_with?, end_with?
• Operators
  • == vs ===
  • <=>
  • <, >, >=, <=
• File
  • basename
  • delete
  • dirname
  • directory?
  • exist?
  • new
  • open
• Class, Module
  • <
  • new, initialize 🔹
  • inherited
  • superclass
  • alias_method
  • ancestors
  • attr_reader, attr_writer, attr_accessor, attr 🔹
  • class_eval, module_eval
  • class_exec, , module_exec
  • const_get, const_set, const_defined?
  • define_method 🔺
  • extended, included,
  • module_function 🔺
  • private, private_class_method
  • private_constant 🔸
  • name
• Range
  • .. vs ... 🔸
  • min, max
  • cover?
  • each
• Regexp
  • named captures 🔸
  • =~
  • match, match?
• Hash
  • [], []=
  • dig 🔹
  • each, each_pair, each_key, each_value 🔹
  • fetch
  • has_key?, key?, has_value?
  • invert
  • key
  • keys, values
  • merge, merge!, reverse_merge, reverse_merge! 🔹
  • transform_keys, transform_keys!, transform_values, transform_values! 🔸
• Time
  • now, utc 🔹
  • day, month, year, hour, minute, sec
  • wday
  • monday? .. sunday?
  • zone
  • strftime
  • iso8601 🔹
  • to_s(:db)
• Difference between strings and symbols 🔸
• Difference between local, instance and global variables 🔹
• Difference between class (static) and instance methods 🔹
• Procs and lambdas 🔸
• Exceptions handling 🔸
• Monkey-patching 🔺
• Mixins 🔺
• ENV
• Enumerator 🔺
  • Enumerator::Lazy
• NotImplementedError 🔺
• OpenStruct
• &.
• Shorthand blocks syntax (&:)
• SecureRandom

ActiveSupport

• Core extensions
  • Array
    • deep_dup
    • extract_options! 🔸
    • in_groups, in_groups_of
    • to_param
    • to_query
    • to_sentence
    • without
    • wrap
  • Class
    • class_attribute 🔺
    • descendants
    • subclasses
  • Date, DateAndTime
    • beginning_of_day, end_of_day
    • current, tomorrow, yesterday 🔹
    • days_ago, months_ago, years_ago
    • future?, past?, today?
    • on_weekday?, on_weekend?
    • in_time_zone
  • Enumerable
    • exclude
    • index_by
    • many?
    • pluck 🔸
    • sum
    • without
  • Hash
    • assert_valid_keys
    • compact, compact!
    • deep_dup
    • deep_merge, deep_merge! 🔸
    • deep_stringify_keys, deep_stringify_keys!, deep_symbolize_keys, deep_symbolize_keys! 🔸
    • deep_transform_keys, deep_transform_keys! 🔸
    • except, except!, extract!
    • slice, slice!
    • with_defaults, with_defaults!
  • Kernel
    • silence_warnings
  • Module
    • alias_attribute
    • delegate 🔹
    • delegate_missing_to
    • deprecate
  • Object
    • presence, present? 🔹
    • presence_in
    • with_options
  • Range
    • overlaps?
  • String
    • blank? 🔹
    • html_safe
    • squish, squish!
    • truncate
    • truncate_words
• Difference between try, try! and &. 🔺
• ArrayInquirer 🔺
• Benchmarkable
• Cache 🔺
  • Available store types
  • NullStore
• Callbacks 🔺
• Concern 🔹
• Configurable
• CurrentAttributes 🔺
• Duration
• HashWithIndifferentAccess 🔸
• Inflector
  • camelize 🔹
  • classify
  • constantize, safe_constantize 🔸
  • dasherize
  • deconstantize 🔸
  • demodulize 🔸
  • foreign_key
  • humanize
  • ordinalize
  • parameterize
  • pluralize, singularize
  • tableize
  • titleize
  • transliterate
  • underscore 🔹
  • upcase_first
• MessageEncryptor
• MessageVerifier
• Notifications, Subscriber
• NumberHelper
  • number_to_currency
  • number_to_delimited
  • number_to_human
  • number_to_human_size
  • number_to_percentage
  • number_to_phone
  • number_to_rounded
• OrderedOptions
• RangeWithFormat
• Rescuable 🔸
• StringInquirer 🔸