Macro py_format 

macro_rules! py_format {
    ($py: expr, $($arg:tt)*) => { ... };
}

This macro is analogous to Rust’s format! macro, but returns a PyString instead of a String.

Arguments

The arguments are exactly like format!, but with py (a Python token) as the first argument:

Interning Advantage

If the format string is a static string and all arguments are constant at compile time, this macro will intern the string in Python, offering better performance and memory usage compared to PyString::from_fmt.

Python::attach(|py| {
    let py_string: Bound<'_, PyString> = py_format!(py, "{} {}", "hello", "world").unwrap();
    assert_eq!(py_string.to_string(), "hello world");
});