Unable to read file contents to string - Result does not implement any method in scope named `read_to_string`

Question

I followed the code to open a file from Rust by Example:

use std::{env, fs::File, path::Path};

fn main() {
    let args: Vec<_> = env::args().collect(         


        

Answer 1

You can also use "?" as well,

let mut file = File::open(&path)?;

But in that case, your method should return Result

like,

fn read_username_from_file() -> Result {
    let mut f = File::open("hello.txt")?;
    let mut s = String::new();
    f.read_to_string(&mut s)?;
    Ok(s)
}

If you can not return Result then you have to handle error case using expect (mentioned in the accepted answer) or using following way,

let file = File::open(&opt_raw.config);

let file = match file {                                                
    Ok(file) => file,                                                  
    Err(error) => {                                                    
        panic!("Problem opening the file: {:?}", error)                
    },                                                                 
};                                                                     

For more information, please refer this link