class Struct < Object

Subclasses: Struct::Tms

A Struct is a convenient way to bundle a number of attributes together, using accessor methods, without having to write an explicit class.

The Struct class is a generator of specific classes, each one of which is defined to hold a set of variables and their accessors. In these examples, we'll call the generated class “CustomerClass,” and we'll show an example instance of that class as “CustomerInst.”

In the descriptions that follow, the parameter aSymbol refers to a symbol, which is either a quoted string or a Symbol (such as :name).

mixins

Enumerable
collect, detect, each_with_index, entries, find, find_all, grep, include?, map, max, member?, min, reject, select, sort, to_a

class methods

new
Struct.new( [aString] [, aSym]+ ) → CustomerClass

Creates a new class, named by aString, containing accessor methods for the given symbols. If the name aString is omitted, an anonymous structure class will be created. Otherwise, the name of this struct will appear as a constant in class Struct, so it must be unique for all Structs in the system and should start with a capital letter.

Struct.new returns a new Class object, which can then be used to create specific instances of the new structure. The remaining methods listed below (class and instance) are defined for this generated class. See the description that follows for an example.

new
CustomerClass.new( [anObject]+ ) → CustomerInst
Creates a new instance. The number of actual parameters must be less than or equal to the number of attributes defined for this class; unset parameters default to nil. Passing too many parameters will raise an ArgumentError.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe.name "Joe Smith" joe.zip 12345
members
CustomerClass.members → anArray
Returns an array of strings representing the names of the instance variables.
Customer = Struct.new( "Customer", :name, :address, :zip ) Customer.members ["name", "address", "zip"]

instance methods

==
CustomerInst == anOtherStructtrue or false
Equality—Returns true if anOtherStruct is equal to this one: they must be of the same class as generated by Struct.new, and the values of all instance variables must be equal (according to Object#==).
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joejr = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) jane = Customer.new( "Jane Doe", "456 Elm, Anytown NC", 12345 ) joe == joejr true joe == jane false
[ ]
CustomerInst[ aSymbol ] → anObject
CustomerInst[ anInteger ] → anObject
Attribute Reference—Returns the value of the instance variable named by aSymbol, or indexed (0..length-1) by anInteger. Will raise NameError if the named variable does not exist, or IndexError if the index is out of range.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe["name"] "Joe Smith" joe[:name] "Joe Smith" joe[0] "Joe Smith"
[ ]=
CustomerInst[ aSymbol ] = anObjectanObject
CustomerInst[ anInteger ] = anObjectanObject
Attribute Assignment—Assigns to the instance variable named by aSymbol or anInteger the value anObject and returns it. Will raise a NameError if the named variable does not exist, or an IndexError if the index is out of range.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe["name"] = "Luke" joe[:zip] = "90210" joe.name "Luke" joe.zip "90210"
each
CustomerInst.each {| anObject | block } → CustomerInst
Calls block once for each instance variable, passing the value as a parameter.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe.each {|x| puts(x) }

produces:

Joe Smith 123 Maple, Anytown NC 12345
length
CustomerInst.length → anInteger
Returns the number of instance variables.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe.length 3
members
CustomerInst.members → anArray
Returns an array of strings representing the names of the instance variables.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe.members ["name", "address", "zip"]
size
CustomerInst.size → anInteger
Synonym for Struct#length.
to_a
CustomerInst.to_a → anArray
Returns the values for this instance as an array.
Customer = Struct.new( "Customer", :name, :address, :zip ) joe = Customer.new( "Joe Smith", "123 Maple, Anytown NC", 12345 ) joe.to_a[1] "123 Maple, Anytown NC"
values
CustomerInst.values → anArray
Synonym for to_a.
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