File operation: read, write and append.
Code
use std::fs;
use std::io::prelude::*;
fn main() {
// write file
let age = 12;
let mut f = fs::File::create("newfile").unwrap();
// 1st way: write_all
f.write_all(b"some content here\n").unwrap();
// 2nd way: write!
write!(f, "age: {}\n", age).unwrap();
// 3rd way: fs::write
fs::write("sample.txt", "sample code").unwrap();
// read file
let mut fread = fs::File::open("newfile").unwrap();
let mut content = String::new();
// 1st way: File.read_to_string
fread.read_to_string(&mut content).unwrap();
println!("File content(1):\n{}", content);
// 2nd way: fs::read_to_string
let fcontent = fs::read_to_string("newfile").unwrap();
println!("File content(2):\n{}", fcontent);
// append mode
// Use OpenOptions to open file in append mode
let mut fappend = fs::OpenOptions::new()
.append(true)
.open("newfile")
.unwrap();
write!(fappend, "append one line\n").unwrap();
let fcontent = fs::read_to_string("newfile").unwrap();
println!("File content(3):\n{}", fcontent);
}
Result:
File content(1):
some content here
age: 12
File content(2):
some content here
age: 12
File content(3):
some content here
age: 12
append one line
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