What's the most straightforward way to convert a hex string into a float? (without using 3rd party crates).
Does Rust provide some equivalent to Python's struct.unpack('!f', bytes.fromhex('41973333'))
See this question for Python & Java, mentioning for reference.
This is quite easy without external crates:
fn main() {
// Hex string to 4-bytes, aka. u32
let bytes = u32::from_str_radix("41973333", 16).unwrap();
// Reinterpret 4-bytes as f32:
let float = unsafe { std::mem::transmute::<u32, f32>(bytes) };
// Print 18.9
println!("{}", float);
}
There's f32::from_bits which performs the transmute in safe code. Note that transmuting is not the same as struct.unpack, since struct.unpack lets you specify endianness and has a well-defined IEEE representation.
{from,to}_{be,le}. f32::from_bits also has the advantage to deal with NaN values correctly.
from_bits handles NaN more correctly; it's just more conservative. Whether signalling NaNs can actually cause unsafe behaviour is still under debate.