String interpolation in Rust is done using the format!() macro. The syntax for string interpolation is similar to other programming languages, with curly braces {} used to indicate where the interpolated values should be placed.
Here is the basic syntax of the format!() macro:
let string = format!("My name is {} and I am {} years old", name, age);
In this example, the {} characters within the string represent placeholders for variables. When the format!() macro is executed, the variables are substituted into the placeholders, and the resulting string is returned.
Here's a simple example that demonstrates string interpolation in Rust:
let name = "John";
let age = 42;
let message = format!("My name is {} and I am {} years old", name, age);
println!("{}", message); // Output: My name is John and I am 42 years old
In this example, the values of the name and age variables are interpolated into the string using the format!() macro. The resulting string is stored in the message variable and printed to the console using the println!() macro.
The format!() macro also supports named placeholders, which can make the code more readable and maintainable. Here's an example that demonstrates named placeholders:
let person = ("John", 42);
let message = format!("My name is {name} and I am {age} years old", name=person.0, age=person.1);
println!("{}", message); // Output: My name is John and I am 42 years old
In this example, we use tuple to store name and age. The name and age values are passed in as named arguments to the format!() macro, making the code more readable.
That's how string interpolation in Rust works with the format!() macro.