How to pretty-print inlined variables when formatting strings

Normally one can print strings the following way: println!("{:#?}", foo) where the {:#?} syntax will make a pretty-print of the value. But I know it’s also possible to inline the variable directly in the string between the curly braces, instead of listing it as a second argument to the macro, like so: println!("{foo}").

My question is – can I combine the pretty-print syntax and inlining the variable in the string?

I found out about the shorthand syntax from clippy’s docs, but I couldn’t find (or understand) how to combine it with pretty-print (if it’s at all possible).

>Solution :

Simply place the variable name before the colon:

fn main() {
    let foo = 3;


  • :#? is pretty-printed Debug output
  • :? is normal Debug output
  • no modifier is Display output

Display is for user-facing output

Debug is for output when debugging, also used for panic messages

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