Updating a Hashmap inside for loop

[PoisonAlien]

Hello,
I have a Hashmap which I am trying to update inside the for loop, based on if else statement.

fn makemethdb(file: &String) {
    let bed = File::open(file).expect("Can not!");
    let bedbuf = BufReader::new(bed);

    let mut methmap: HashMap<String, String> = HashMap::new();
    let mut chr: String = String::new();

    for line in bedbuf.lines(){
        let line = line.unwrap();
        let linespl: Vec<&str> = line.split('\t').collect();
        
        let mut linechr: String = linespl[0].to_owned().to_string();
        let mut linestart: String = linespl[1].to_owned().to_string();
        let mut mval: String = linespl[2].to_owned().to_string();   

        if chr.is_empty(){
            let chr = linechr;
            methmap.insert(linestart, mval);
        }else {
            if chr == linechr{
                methmap.insert(linestart, mval);
            }else{
                let mutmethmap: HashMap<String, String> = HashMap::new();
                let chr = linechr;
                methmap.insert(linestart, mval);
            }
        }
    }
}

I am getting value borrowed here after move error at first occurance of methmap inside for loop. How do I resolve the issue?
I apologize is advance, I am quite new to the language.

[parasyte]

Hi!

First, a few quick tips: you can remove a lot of the type annotations and let the compiler infer the types for you. And you can use https://play.rust-lang.org/ to do simple tests and share code snippets. It is also helpful to provide the full error message.

When I copy-paste that code snippet into the playground, there is no error (including the necessary use statements) but there are a lot of warnings showing that you are creating variable bindings that are unused. I'm guessing this is not actually the same code that you are having problems with?

[naim]

The code seems to compile, although the use of to_string after to_owned is redundant (type is already owned, why clone it again?) and all cases of the if will insert (linestart, mval) into methmap.

[PoisonAlien]

Hello both,

Thanks for the reply. I have updated a reproducible code on playground (I hope my code is readable enough).

Rust Playground

Could you please suggest me how to circumvent the issue?

[alice]

Change the existing variables instead of shadowing them with a new variable.

 } else {
     methdb.insert(chr.clone(), methmap);
-    let mut methmap: HashMap<String, String> = HashMap::new();
-    let chr = linechr;
+    methmap = HashMap::new();
+    chr = linechr;
     methmap.insert(linestart, mval);
 }

playground