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Ruby Ruby Objects and Classes Build a Bank Account Class Part 2: Transactions, credits, and debits

Posted by Colin Xu
Colin Xu
4,967 Points

Why and how are symbols used as keys inside the add_transaction method?

I don't remember where any of the videos explained exactly what the purpose of a symbol was, so I'm not quite sure how they are used.

For example, what difference would it make if the keys "description" and "amount" were used instead of :description and :amount? And what difference does it make if the colon is a prefix or a suffix?

brian biggers
brian biggers
8,556 Points
brian biggers
brian biggers
8,556 Points

This wasn't explained very well. He was using strings as keys up until this point and he gives no explanation as to why he starts using symbols all of a sudden. Smh

1 Answer

mkmk
mkmk
15,897 Points

In Ruby, symbols are immutable strings, written with a colon prefix, like :symbol. They are used to save memory, for faster running applications.
When creating a hash, if the keys are not explicitly made "strings", they default to symbols like in the video.
The colon afterwards is for assignment, rather than =>

Learn more from this Stack Overflow post (and the answer's included links):
https://stackoverflow.com/questions/8189416/why-use-symbols-as-hash-keys-in-ruby