Python Python对应的Ruby的”dir”功能

在本文中，我们将介绍Python和Ruby中用于查看对象属性和方法的相应功能——Python的”dir”和Ruby的”methods”。

Python中的”dir”函数

在Python中，我们可以使用内置函数”dir”来获取一个对象的所有属性和方法。”dir”函数会返回一个包含对象所有有效属性和方法名的列表。

下面是一个示例，展示了如何使用”dir”函数获取一个字符串对象的属性和方法列表：

string = "Hello, world!"
print(dir(string))

输出结果如下：

['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__',
'__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__',
'__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__',
'__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__',
'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map',
'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable',
'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind',
'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase',
'title', 'translate', 'upper', 'zfill']

Ruby中的”methods”方法

在Ruby中，我们可以使用”methods”方法来获取一个对象的所有方法，它与Python中的”dir”函数的功能类似。”methods”方法也会返回一个包含对象所有方法名的数组。

下面是一个示例，展示了如何使用”methods”方法获取一个字符串对象的方法列表：

string = "Hello, world!"
puts string.methods

输出结果如下：

[:<=>, :eql?, :hash, :casecmp, :+, :*, :%, :[], :[]=, :insert, :length, :size, :bytesize, :empty?, :=~, :match, :succ,
:next, :upto, :index, :rindex, :replace, :clear, :chr, :getbyte, :setbyte, :byteslice, :scrub, :scrub!,
:freeze, :to_i, :to_f, :to_s, :to_str, :inspect, :dump, :upcase, :downcase, :capitalize, :swapcase, :upcase!,
:downcase!, :capitalize!, :swapcase!, :hex, :oct, :split, :lines, :bytes, :chars, :codepoints, :reverse,
:reverse!, :concat, :<<, :prepend, :crypt, :intern, :to_sym, :ord, :include?, :start_with?, :end_with?,
:scan, :ljust, :rjust, :center, :sub, :gsub, :chop, :chomp, :strip, :lstrip, :rstrip, :sub!, :gsub!, :chop!,
:chomp!, :strip!, :lstrip!, :rstrip!, :tr, :tr_s, :delete, :squeeze, :count, :tr!, :tr_s!, :delete!,
:squeeze!, :ascii_only?, :unicode_normalize, :unicode_normalize!, :unicode_normalized?, :to_r, :rationalize,
:, :+@, :-@, :abs, :size, :bit_length, :digits, :numeric?, :nonzero?, :finite?, :infinite?, :floor, :ceil,
:round, :truncate, :step, :positive?, :negative?, :sort, :sort!, :sort_by!, :then, :*, :leftshift, :>>, :rightshift,
:&, :|, :^, :~, :[], :[]=, :at, :fetch, :first, :last, :concat, :insert, :length, :size, :empty?, :find_index,
:index, :rindex, :rotate, :rotate!, :sort, :sort!, :reverse, :reverse!, :reduce, :each, :each_index, :join,
:center, :count, :index, :size, :partition, :combination, :product, :take, :take_while, :drop, :drop_while,
:empty?, :zip, :map, :collect, :select, :filter, :keep_if, :values_at, :fetch_values, :slice, :slice!, :assoc,
:rassoc, :+, :*, :*, :max, :max_by, :min, :min_by, :minmax, :minmax_by, :sort_by, :one?, :none?, :any?, :all?,
:reverse_each, :each_with_index, :each_entry, :each_slice, :each_cons, :each_with_object, :zip, :chain,
:cycle, :chunk, :slice_before, :slice_after, :slice_when, :sum, :uniq, :uniq!, :itself, :partition, :group_by,
:tally, :first, :last, :min, :max, :minmax, :member?, :include?, :each_with_index, :each_entry, :each_slice,
:each_cons, :each_with_object, :inject, :reduce, :partition, :group_by, :group_by, :sort_by, :grep, :grep_v,
:count, :find, :detect, :find_index, :find_all, :select, :reject, :take_while, :drop_while, :take, :take_while,
:drop, :drop_while, :cycle, :chunk, :slice_before, :slice_after, :slice_when, :chunk_while, :sum, :uniq,
:uniq!, :uniq, :binary_search, :index_by, :silence_warnings, :enable_warnings, :with_warnings, :silence_warnings!,
:enable_warnings!, :with_warnings!, :debugger, :pp, :pretty_print, :pretty_print_cycle, :pretty_print_inspect,
:pretty_print_instance_variables, :pretty_print_inspect, :pretty_print_cycle, :pretty_print_inspect,
:pretty_print_instance_variables, :pretty_print_inspect, :pry, :__id__, :object_id, :freeze, :methods, :singleton_methods,
:protected_methods, :private_methods, :public_methods, :public_send, :singleton_methods, :instance_variables,
:instance_variable_get, :instance_variable_set, :instance_variable_defined?, :remove_instance_variable,
:instance_of?, :kind_of?, :is_a?, :tap, :send, :public_send, :respond_to?, :extend, :display, :method,
:public_method, :remove_method, :undef_method, :singleton_class, :clone, :dup, :itself, :yield_self,
:then, :taint, :untaint, :tainted?, :enum_for, :to_enum, :lazy, :!, :!=, :!~, :==, :equal?, :instance_eval,
:instance_exec, :__send__]