I've seen both to_string() and to_owned() used for converting a string literal into a String. What are the differences between these two options, and when should you use which one?

You should always be using to_owned(). to_string() is the generic conversion to a String from any type implementing the ToString trait. It uses the formatting functions and therefor might end up doing multiple allocations and running much more code than a simple to_owned() which just allocates a buf…

I'm more fond of using .into(). It requires adding type hints in some cases, but for most cases it is shorter than the alternatives. Especially when passing a string literal to a function that requires String.

This may be fixed in the future with specialization, as str could implement ToString directly instead of having it go through the generic impl<T> ToString for T where T: Display {} implementation, which employs the formatting framework. But currently I do concur with your recommendation.

[image] DroidLogician: This may be fixed in the future with specialization, as str could implement ToString directly instead of having it go through the generic impl<T> ToString for T where T: Display {} implementation, which employs the formatting framework. But currently I do concur with your …

I found that my opinion on this has changed significantly over the past 12 months as I have grown more experienced with Rust. I now strongly prefer to_owned() for string literals over either of to_string() or into(). What is the difference between String and &str? An unsatisfactory answer is "one…

Not if you mentally read to_string as to_String :slight_smile:

For you, okay. But, someone else down the line, probably much less experienced than you, will be trying to read and understand your code, so clear intent is very helpful. (And, sometimes that less-experienced person is you, six months -- or five years -- later.)

Is there an explanation somewhere why you would turn a &str to String (other than make the borrow checker stop nagging)?

To be able to change the string or to ensure that the string stays alive. Please don't post on old topics and instead create a new topic.

`to_string()` vs `to_owned()` for string literals

help

vitalyd March 6, 2017, 11:09pm 7

Not if you mentally read to_string as to_String

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`to_string()` vs `to_owned()` for string literals

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