Is it possible to use format! in Substrate runtime?

Asked Jan 14 '22 at 07:44

Active Jan 15 '22 at 02:43

Viewed 153 times

From the link, It seems format! can work in Substrate runtime.

let hello_world = sp_std::fmt::format!("Hello,{}","world");

I want to have a variable hello_world and use it for latter。

But I always get an error : could not find format in fmt

I have searched for a long time, I also refs: how to use format! in no_std

I have been confused for several days.

The link is not correct? Are there some stories behind this?

edited Jan 15 '22 at 02:43

asked Jan 14 '22 at 07:44

gfan

If you're trying to debug substrate then [this might help](https://docs.substrate.io/v3/runtime/debugging/). – forgetso Jan 14 '22 at 08:56
I need a variable from the format! result. – gfan Jan 15 '22 at 02:43
I just tried `panic!(format!("Hi {}", 1234));` in my pallet and the tests now panic. No compile error. What kind of error do you get? – Oliver Tale-Yazdi Jan 17 '22 at 12:39
can not find `format!` – gfan Jan 18 '22 at 09:00
Maybe you can use [my pallet](https://github.com/perun-network/perun-polkadot-pallet/blob/39a6176cb4a78aac329bddd6d9dc8b307b03fea7/src/lib.rs#L225) to debug yours? It is possible to add a `format!` to the extrinsic. @gfan – Oliver Tale-Yazdi Jan 19 '22 at 09:20

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