Is there a default difference between methods with '!' and without, in ruby?

Question

collect v collect!

flatten v flatten!

and so on..

Yes and no. *Conventionally* they're used for methods that mutate internal state, perform operations that affect external state (e.g., write to a database), handle exceptions differently, etc. But the `!` is just part of the method name. — Dave Newton, Jan 14 '14 at 13:57

score 2 · Accepted Answer · answered Jan 14 '14 at 13:57

In ruby the main difference is that, the ! methods are selfish, i.e. they apply the changes to the self object. They return nil, when no changes are done, while the non-! methods create new modified object.

In Rails the difference is that, the ! methods are safe versions of non-! methods, that means the ! methods raises an exception when the code encountered an error during execution, while non-! methods just return error state, usually false condition.

Thanks for the answer and the extra rails info – HandDisco Jan 14 '14 at 14:24 — HandDisco, Jan 14 '14 at 14:24

Is there a default difference between methods with '!' and without, in ruby?

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