Parsing variable from delimited file - rust

Question

I have some file content which delimited by pipe | symbol. Named, important.txt.
1|130|80|120|110|E
2|290|420|90|70|B
3|100|220|30|80|C
Then, I use Rust BufReader::split to read its content.
use std::error::Error;
use std::fs::File;
use std::io::BufReader;
use std::io::Prelude::*;
use std::path::Path;
fn main() {
let path = Path::new("important.txt");
let display = path.display();
//Open read-only
let file = match File::open(&path) {
Err(why) => panic!("can't open {}: {}", display,
Error::description(why)),
Ok(file) => file,
}
//Read each line
let reader = BufReader::new(&file);
for vars in reader.split(b'|') {
println!("{:?}\n", vars.unwrap());
}
}
The problem is, vars.unwrap() would return bytes instead of string.
[49]
[49, 51, 48]
[56, 48]
[49, 50, 48]
[49, 49, 48]
[69, 10, 50]
[50, 57, 48]
[52, 50, 48]
[57, 48]
[55, 48]
[66, 10, 51]
[49, 48, 48]
[50, 50, 48]
[51, 48]
[56, 48]
[67, 10]
Do you have any ideas how to parse this delimited file into variable in Rust?

Answer 1

Since your data is line-based, you can use BufRead::lines:
use std::io::{BufReader, BufRead};
fn main() {
let input = r#"1|130|80|120|110|E
2|290|420|90|70|B
3|100|220|30|80|C
"#;
let reader = BufReader::new(input.as_bytes());
for line in reader.lines() {
for value in line.unwrap().split('|') {
println!("{}", value);
}
}
}
This gives you an iterator over Strings for each line in the input. You then use str::split to get the pieces.
Alternatively, you can take the &[u8] you already have and make a string from it with str::from_utf8:
use std::io::{BufReader, BufRead};
use std::str;
fn main() {
let input = r#"1|130|80|120|110|E
2|290|420|90|70|B
3|100|220|30|80|C
"#;
let reader = BufReader::new(input.as_bytes());
for vars in reader.split(b'|') {
let bytes = vars.unwrap();
let s = str::from_utf8(&bytes).unwrap();
println!("{}", s);
}
}
You may also want to look into the csv crate if you are reading structured data like a CSV that just happens to be pipe-delimited.