When should I use Struct vs. OpenStruct?

ruby struct
ehsanul picture ehsanul · Jul 24, 2009 · Viewed 64.8k times · Source

In general, what are the advantages and disadvantages of using an OpenStruct as compared to a Struct? What type of general use-cases would fit each of these?

Answer

Pesto picture Pesto · Jul 24, 2009

With an OpenStruct, you can arbitrarily create attributes. A Struct, on the other hand, must have its attributes defined when you create it. The choice of one over the other should be based primarily on whether you need to be able to add attributes later.

The way to think about them is as the middle ground of the spectrum between Hashes on one side and classes on the other. They imply a more concrete relationship amongst the data than does a Hash, but they don't have the instance methods as would a class. A bunch of options for a function, for example, make sense in a hash; they're only loosely related. A name, email, and phone number needed by a function could be packaged together in a Struct or OpenStruct. If that name, email, and phone number needed methods to provide the name in both "First Last" and "Last, First" formats, then you should create a class to handle it.

Related questions

When to use Struct instead of Hash in Ruby?

I don't have much programming experience. But, to me, Struct seems somewhat similar to Hash. What can Struct do well? Is there anything Struct can do, that Hash cannot do? After googling, the concept of Struct is important in C, …

Read More
Named Parameters in Ruby Structs

I'm pretty new to Ruby so apologies if this is an obvious question. I'd like to use named parameters when instantiating a Struct, i.e. be able to specify which items in the Struct get what values, and default the …

Read More
How to check if a value exists in an array in Ruby

I have a value 'Dog' and an array ['Cat', 'Dog', 'Bird']. How do I check if it exists in the array without looping through it? Is there a simple way of checking if the value exists, nothing more?

Read More