1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/// Find all unique elements in a collection (elements that appear exactly once).
///
/// # Arguments
/// * `collection` - A slice of items.
///
/// # Returns
/// * `Vec<T>` - A vector containing only the elements that appear exactly once in the input.
///
/// # Examples
/// ```rust
/// use lowdash::find_uniques;
/// let numbers = vec![1, 2, 2, 3, 3, 4];
/// let result = find_uniques(&numbers);
/// assert_eq!(result, vec![1, 4]);
/// ```
///
/// ```rust
/// use lowdash::find_uniques;
/// let words = vec!["apple", "banana", "apple", "cherry"];
/// let result = find_uniques(&words);
/// assert_eq!(result, vec!["banana", "cherry"]);
/// ```
///
/// ```rust
/// use lowdash::find_uniques;
///
/// #[derive(Debug, Clone, PartialEq, Eq, Hash)]
/// struct Person {
/// name: String,
/// age: u32,
/// }
///
/// let people = vec![
/// Person { name: "Alice".to_string(), age: 25 },
/// Person { name: "Bob".to_string(), age: 30 },
/// Person { name: "Alice".to_string(), age: 25 },
/// ];
///
/// let result = find_uniques(&people);
/// assert_eq!(result, vec![Person { name: "Bob".to_string(), age: 30 }]);
/// ```
pub fn find_uniques<T>(collection: &[T]) -> Vec<T>
where
T: Clone + Eq + std::hash::Hash,
{
use std::collections::HashMap;
let mut counts = HashMap::new();
// Count occurrences
for item in collection {
*counts.entry(item).or_insert(0) += 1;
}
// Collect items that appear exactly once
collection
.iter()
.filter(|item| counts.get(item) == Some(&1))
.cloned()
.collect()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_find_uniques_numbers() {
let collection = vec![1, 2, 2, 3, 3, 4];
let result = find_uniques(&collection);
assert_eq!(result, vec![1, 4]);
}
#[test]
fn test_find_uniques_strings() {
let collection = vec!["apple", "banana", "apple", "cherry"];
let result = find_uniques(&collection);
assert_eq!(result, vec!["banana", "cherry"]);
}
#[test]
fn test_find_uniques_empty() {
let collection: Vec<i32> = vec![];
let result = find_uniques(&collection);
assert_eq!(result, Vec::<i32>::new());
}
#[test]
fn test_find_uniques_all_duplicates() {
let collection = vec![1, 1, 2, 2, 3, 3];
let result = find_uniques(&collection);
assert_eq!(result, Vec::<i32>::new());
}
#[test]
fn test_find_uniques_all_unique() {
let collection = vec![1, 2, 3, 4, 5];
let result = find_uniques(&collection);
assert_eq!(result, vec![1, 2, 3, 4, 5]);
}
#[test]
fn test_find_uniques_with_struct() {
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct Person {
name: String,
age: u32,
}
let people = vec![
Person {
name: "Alice".to_string(),
age: 25,
},
Person {
name: "Bob".to_string(),
age: 30,
},
Person {
name: "Alice".to_string(),
age: 25,
},
];
let result = find_uniques(&people);
assert_eq!(
result,
vec![Person {
name: "Bob".to_string(),
age: 30,
}]
);
}
}