I passed a vec parameter into function in rust like this:

pub fn songs(playlist_records: Vec<QueryFavorites>) -> Vec<MusicResponse> {
}

first step I get the ids from playlist_records to execute a query, this is the code:

let ids: Vec<String> = playlist_records
        .into_iter()
        .map(|item| item.source_id.to_string())
        .collect();

when I use the playlist_records second time to fetch the field after get the query result:

for query_song in &results {
   let favTime: Vec<QueryFavorites> = playlist_records
       .into_iter()
       .filter(|item| item.source_id == query_song.source_id)
       .collect();
}

it tell me the playlist_records was moved. This is the message:

`playlist_records` moved due to this method call, in previous iteration of loop

I tried to borrow the playlist_records like this:

let ids: Vec<String> = &playlist_records
        .into_iter()
        .map(|item| item.source_id.to_string())
        .collect();

seems did not work, what should I do to reuse the playlist_records?

CodePudding user response：

Change into_iter to use iter, since into_iter consumes the collection while iter iterates by reference and doesn't consume, see more about the difference here:

playground

let ids: Vec<String> = playlist_records
    .iter()
    .map(|item| item.source_id.to_string())
    .collect();

let favTime: Vec<&QueryFavorites> = playlist_records
  .iter()
  .filter(|item| item.source_id == "someid")
  .collect();

which however means your favTime will be of Vec<&QueryFavorites> type if that's fine with you. Otherwise, you can always clone the iterator.

let favTime: Vec<QueryFavorites> = playlist_records
  .iter()
  .cloned()
  .filter(|item| item.source_id == "someid")
  .collect();

playground