Small example to get lower bound of word counting of a file.

word_count.rs

use rayon::prelude::*;                                                              
use std::collections::HashMap;                                                      
                                                                                    
fn main() {                                                                         
    let buf = std::fs::read_to_string("data/big.txt").unwrap();                     
    let word_count = buf                                                            
        .par_lines()                                                                
        .map(|line| {                                                               
            let mut frequency: HashMap<&str, u32> = HashMap::new();                 
            for word in line.split(' ') {                                           
                *frequency.entry(word).or_insert(0) += 1;                           
            }                                                                       
            frequency                                                               
        })                                                                          
        .reduce(HashMap::new, |mut acc, freq| {                                     
            for (k, v) in freq {                                                    
                *acc.entry(k).or_insert(0) += v;                                    
            }                                                                       
            acc                                                                     
        });                                                                         
    println!("Word count {}", word_count.len());                                                                               
}