rust - How do I sort a map by order of insertion? -


i have tried using hashmap , btreemap neither have worked:

use std::collections::{btreemap, hashmap};  fn main() {     let mut btreemap = btreemap::new();     println!("btreemap");     btreemap.insert("z", "1");     btreemap.insert("t", "2");     btreemap.insert("r", "3");     btreemap.insert("p", "4");     btreemap.insert("k", "5");     btreemap.insert("w", "6");     btreemap.insert("g", "7");     btreemap.insert("c", "8");     btreemap.insert("a", "9");     btreemap.insert("d", "0");     (key, value) in btreemap {         println!("{} {}", key, value);     }     println!("hash map");     let mut hashmap = hashmap::new();     hashmap.insert("z", "1");     hashmap.insert("t", "2");     hashmap.insert("r", "3");     hashmap.insert("p", "4");     hashmap.insert("k", "5");     hashmap.insert("w", "6");     hashmap.insert("g", "7");     hashmap.insert("c", "8");     hashmap.insert("a", "9");     hashmap.insert("d", "0");     (key, value) in hashmap {         println!("{} {}", key, value);     } }

when run via rust playground, result not sorted order of insertion; btreemap appears ordered alphabetically (prints a c d g k p r t w z, along numbers) , hashmap seems ordered randomly (prints z c d r p t g wk ).

i've looked through rust standard library documentation , don't see other maps.

the default collections not track order of insertion. if wish sort that, need either find different collection does track it, or track yourself.


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