How to find the Item with Minimum Number of Occurrences in a Vector in Rust - Step by Step Examples

How to find the Item with Minimum Number of Occurrences in a Vector in Rust ?

Answer

To find the item with the minimum number of occurrences in a Vector in Rust, you can use a HashMap to count the occurrences of each item and then find the item with the minimum count.


✐ Examples

1 Find Item with Minimum Occurrences in a Vector of Strings

In this example,

  1. We start by importing the necessary collections: std::collections::HashMap.
  2. We create a vector named vec containing several string elements.
  3. We create a HashMap named counts to store the occurrences of each string in the vector. The keys of the HashMap will be the strings, and the values will be their counts.
  4. We use a for loop to iterate through each element in the vector. For each element, we increment its count in the HashMap using the entry method to handle missing keys.
  5. We initialize two variables, min_item and min_count, to keep track of the item with the minimum occurrences and its count. min_count is initialized to usize::MAX to ensure any count will be lower initially.
  6. We iterate through the HashMap to find the item with the lowest count. If we find an item with a count lower than min_count, we update min_item and min_count.
  7. Finally, we print the item with the minimum number of occurrences to standard output using println!.

Rust Program

use std::collections::HashMap;

fn main() {
    // Step 2: Create a vector of strings
    let vec = vec!["apple", "banana", "apple", "orange", "banana", "apple", "kiwi"];
    
    // Step 3: Create a HashMap to count occurrences
    let mut counts = HashMap::new();
    
    // Step 4: Count occurrences of each item in the vector
    for item in vec {
        *counts.entry(item).or_insert(0) += 1;
    }
    
    // Step 5: Initialize variables to find the item with the minimum occurrences
    let mut min_item = "";
    let mut min_count = usize::MAX;
    
    // Step 6: Iterate through the HashMap to find the item with the lowest count
    for (item, &count) in &counts {
        if count < min_count {
            min_item = item;
            min_count = count;
        }
    }
    
    // Step 7: Print the item with the minimum occurrences
    println!("Item with minimum occurrences: {}", min_item);
}

Output

Item with minimum occurrences: kiwi

2 Find Item with Minimum Occurrences in a Vector of Integers

In this example,

  1. We start by importing the necessary collections: std::collections::HashMap.
  2. We create a vector named vec containing several integer elements.
  3. We create a HashMap named counts to store the occurrences of each integer in the vector. The keys of the HashMap will be the integers, and the values will be their counts.
  4. We use a for loop to iterate through each element in the vector. For each element, we increment its count in the HashMap using the entry method to handle missing keys.
  5. We initialize two variables, min_item and min_count, to keep track of the item with the minimum occurrences and its count. min_count is initialized to usize::MAX to ensure any count will be lower initially.
  6. We iterate through the HashMap to find the item with the lowest count. If we find an item with a count lower than min_count, we update min_item and min_count.
  7. Finally, we print the item with the minimum number of occurrences to standard output using println!.

Rust Program

use std::collections::HashMap;

fn main() {
    // Step 2: Create a vector of integers
    let vec = vec![1, 2, 3, 1, 2, 1, 4, 1, 5, 1];
    
    // Step 3: Create a HashMap to count occurrences
    let mut counts = HashMap::new();
    
    // Step 4: Count occurrences of each item in the vector
    for item in vec {
        *counts.entry(item).or_insert(0) += 1;
    }
    
    // Step 5: Initialize variables to find the item with the minimum occurrences
    let mut min_item = 0;
    let mut min_count = usize::MAX;
    
    // Step 6: Iterate through the HashMap to find the item with the lowest count
    for (&item, &count) in &counts {
        if count < min_count {
            min_item = item;
            min_count = count;
        }
    }
    
    // Step 7: Print the item with the minimum occurrences
    println!("Item with minimum occurrences: {}", min_item);
}

Output

Item with minimum occurrences: 3

Summary

In this tutorial, we learned How to find the Item with Minimum Number of Occurrences in a Vector in Rust language with well detailed examples.


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