Rust Programming By Example

Handling files

Let's start with the basics. First, let's open and write into a file:

    use std::fs::File;
    use std::io::{self, Write};

    fn write_into_file(content: &str, file_name: &str) -> io::Result<()> {
      let mut f = File::create(file_name)?;
      f.write_all(content.as_bytes())
    }

Now let's explain this code:

    use std::fs::File;

Nothing fancy, we just import the File type:

   use std::io::{self, Write};

This set of imports is more interesting: we import the io module (self) and the Write trait. For the second, if we didn't import it, we wouldn't be able to use the write_all method (because you need to import a trait to use its methods):

   fn write_into_file(content: &str, file_name: &str) -> io::Result<()> {

We declared a function named write_into_file ...