Borrowed value does not live long enough, Vec<&str>

[LargeCat]

use std::io::{BufReader, BufRead};
use std::io;

fn read_lines(filename: String) -> io::Lines<BufReader<File>> {
    let file = File::open(filename).unwrap(); 
    return io::BufReader::new(file).lines(); 
}

pub fn main() {
    let mut doc_reg: Vec<&str> = vec![];
    let mut attach_reg: Vec<Vec<&str>> = vec![];
    let regcontent = read_lines("./config.txt".to_string());
    for line in regcontent{
        let a = line.unwrap();                              # B point
        let c:Vec<&str> = a.split("||").collect();
        if c.get(0).unwrap() == &"K1"{
            doc_reg = c.clone().drain(1..).collect();
        }else if c.get(0).unwrap() == &"K2" {
            let tempvc: Vec<_> = c.clone().drain(1..).collect();
            attach_reg.push(tempvc.clone());       #A point
        }
        }
}

I add the # A point, then error appers at B point, how to modify to have it works?

[quinedot]

The problem is that a gets dropped at the end of the loop, so you can't hold on to a reference into a beyond the loop or for multiple loops.

It's not a problem for doc_reg because you overwrite the entire vector every time. If you stop doing that, it will probably error too.

The fix is to either hold on to String instead of &str, or to hold on to all the lines from the file. The first way is probably the better way.

[LargeCat]

thanks, great answer solve my problem......