rustHow to read file in Rust

Reading a file in Rust is a straightforward process. The most common way to do this is to use the std::fs::read_to_string function, which takes a path to the file as an argument and returns a Result<String, io::Error>. This function will read the entire contents of the file into a String and return it. Alternatively, you can use the std::fs::read function, which takes a path to the file as an argument and returns a Result<Vec<u8>, io::Error>. This function will read the entire contents of the file into a Vec<u8> and return it.

use std::fs;

fn main() {
    let contents = fs::read_to_string("my_file.txt").expect("Error reading file");
    println!("File contents: {}", contents);
}

Output example:

File contents: This is the contents of my_file.txt

Explanation

In this example, we use the std::fs::read_to_string function to read the contents of a file into a String. We pass the path to the file as an argument to the function, and it returns a Result<String, io::Error>. If the file is successfully read, the Result will contain the contents of the file as a String. If an error occurs, the Result will contain an io::Error describing the error.

We then use the expect method to unwrap the Result and get the contents of the file. If an error occurs, the expect method will panic and print the error message. Finally, we print the contents of the file using the println! macro.

Helpful links

• std::fs::read_to_string
• std::fs::read
• std::result

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