Paths

File paths from the underlying file system are represented by the Path struct, which is created from a string slice containing the full path with Path::new. Suppose hello.txt is an existing file in the current directory; let's write some code to explore it:

// code from Chapter 11/code/paths.rs:use std::path::Path; 
 
fn main() { 
    let path = Path::new("hello.txt"); 
 let display = path.display(); 
     
    // test whether path exists: 
    if path.exists() { 
        println!("{} exists", display); 
    } 
    else { 
        panic!("This path or file does not exist!"); 
    } 
 
    let file = path.file_name().unwrap();    
let extension = path.extension().unwrap();    
let parent_dir = path.parent().unwrap(); 
    println!("This is file {:?} with extension {:?} in folder {:?}", file, extension, parent_dir); 
 
    // Check if the path is a file: 
    if path.is_file() { println!("{} is a file", display);  } 
    // Check if the path is a directory: 
    if path.is_dir() { println!("{} is a directory", display); } 
} 

This code performs the following:

• Prints: This is file "hello.txt" with extension "txt" in folder "".
• The Path::new("e.txt").unwrap_or_else() method creates the file e.txt or panics with an error.
• Tests whether a path is valid. Use the exists() method.
• Uses the create_dir() method to make folders.
• The file_name(), extension() and parent() methods return an Option value, so use unwrap() to get the value. The is_file() and is_dir() methods test respectively whether a path refers to a filename or to a directory.
• The join() method can be used to build paths, and it automatically uses the operating system-specific separator:

let new_path = path.join("abc").join("def"); 
 
// Convert the path into a string slice 
match new_path.to_str() { 
        None => panic!("new path is not a valid UTF-8 sequence"), 
        Some(s) => println!("new path is {}", s), 
      } 

• This prints out the following on a Windows system:

 new path is hello.txt\abc\def