{"id":2435,"date":"2022-04-23T13:05:57","date_gmt":"2022-04-23T18:05:57","guid":{"rendered":"https:\/\/www.becomebetterprogrammer.com\/?p=2435"},"modified":"2022-04-23T13:06:00","modified_gmt":"2022-04-23T18:06:00","slug":"rust-fix-doesnt-implement-std-fmt-display","status":"publish","type":"post","link":"https:\/\/www.becomebetterprogrammer.com\/staging\/4563\/rust-fix-doesnt-implement-std-fmt-display\/","title":{"rendered":"How to Fix `T` doesn’t implement std:fmt:Display in Rust?"},"content":{"rendered":"\n

Developers who come from a JavaScript background, or any other high-level programming language, and are learning Rust might find this language to have a steep learning curve. Oftentimes, many new Rust developers will come across the error doesn't implement std:fmt:Display<\/code> when attempting to print a value that is not a string, like the one we see in the following example.<\/p>\n\n\n\n

fn main() {\n    let mut array_cities: Vec<String> = Vec::new();\n    array_cities.push(\"San Francisco\".to_string());\n    array_cities.push(\"Santo Domingo\".to_string());\n\n    print!(\"testing {}\", array_cities); \/\/ It will error here\n}<\/code><\/pre>\n\n\n\n
If you attempt to execute this piece of logic using cargo run<\/code> it will fail during compilation and will throw an error message similar to the following.<\/p>\n\n\n\n
error[E0277]: `Vec<String>` doesn't implement `std::fmt::Display`\n  --> src\\main.rs:12:26\n   |\n12 |     print!(\"testing {}\", array_cities);\n   |                          ^^^^^^^^^^^^ `Vec<String>` cannot be formatted with the default formatter\n   |\n   = help: the trait `std::fmt::Display` is not implemented for `Vec<String>`\n   = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead\n   = note: this error originates in the macro `$crate::format_args` (in Nightly builds, run with -Z macro-backtrace for more info)<\/code><\/pre>\n\n\n\n
This can be a little discouraging to most JavaScript developers who are used to logging just about anything using console.log<\/code>, regardless of whether the data type of value to log in the terminal was a string, a number, an array, or any other data type, like you can see in the following example.<\/p>\n\n\n\n
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Using console.log with any data type in JavaScript<\/figcaption><\/figure><\/div>\n\n\n\n
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Table of Contents<\/p>\n<\/div>