iterstats 0.7.0

Statistics for rust iterators.
Documentation 
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
135
136
137
138
139
140
141
142
143
144

//! Calculate the median.

use crate::Iterstats;

/// Calculate the mean of an iterator.
pub trait Median<A = Self>: Sized {
    /// The type of the output.
    type Output;

    /// Calculate the mean.
    fn median<I: Iterator<Item = A>>(iter: I) -> Self::Output;
}

macro_rules! median_impl {
    (partial_ord: $typ:ty) => {
        impl Median for $typ {
            type Output = $typ;

            fn median<I: Iterator<Item = Self>>(iter: I) -> Self::Output {
                let mut v = iter.filter(|i| !i.is_nan()).collect::<Vec<_>>();
                v.sort_unstable_by(|a, b| a.partial_cmp(b).unwrap());
                if v.len() % 2 == 0 {
                    (v[v.len() / 2 - 1] + v[v.len() / 2]) / 2.
                } else {
                    v[v.len() / 2]
                }
            }
        }

        impl Median for &$typ {
            type Output = $typ;

            fn median<I: Iterator<Item = Self>>(iter: I) -> Self::Output {
                iter.map(|i| *i).median()
            }
        }
    };
    (ord: $typ:ty) => {
        impl Median for $typ {
            type Output = $typ;

            fn median<I: Iterator<Item = Self>>(iter: I) -> Self::Output {
                let mut v = iter.collect::<Vec<_>>();
                v.sort_unstable();
                if v.len() % 2 == 0 {
                    (v[v.len() / 2 - 1] + v[v.len() / 2]) / 2
                } else {
                    v[v.len() / 2]
                }
            }
        }

        impl Median for &$typ {
            type Output = $typ;

            fn median<I: Iterator<Item = Self>>(iter: I) -> Self::Output {
                iter.map(|i| *i).median()
            }
        }
    };
}

median_impl!(partial_ord: f64);
median_impl!(partial_ord: f32);
median_impl!(ord: u128);
median_impl!(ord: u64);
median_impl!(ord: u32);
median_impl!(ord: u16);
median_impl!(ord: u8);
median_impl!(ord: usize);
median_impl!(ord: i128);
median_impl!(ord: i64);
median_impl!(ord: i32);
median_impl!(ord: i16);
median_impl!(ord: i8);
median_impl!(ord: isize);

#[cfg(test)]
mod tests {
    use super::*;
    use paste::paste;

    macro_rules! test_median {
        ($name:ident: $typ:ty as $iter:expr ; into_iter => $expected:expr) => {
            paste! {
                #[test]
                fn [<$name _into_iter>]() {
                    let median = $typ::median($iter.into_iter());
                    assert_eq!(median, $expected)
                }
            }
        };
        ($name:ident: $typ:ty as $iter:expr ; iter => $expected:expr) => {
            paste! {
                #[test]
                fn [<$name _iter>]() {
                    let median = <&$typ>::median($iter.iter());
                    assert_eq!(median, $expected)
                }
            }
        };
        ($name:ident: $typ:ty as $iter:expr => $expected:expr) => {
            test_median!($name: $typ as $iter; iter => $expected);
            test_median!($name: $typ as $iter; into_iter=> $expected);
        };
    }

    test_median!(f64_odd: f64 as [12., 17., 11., 8., 9.] => 11.);
    test_median!(f32_odd: f32 as [12., 17., 11., 8., 9.] => 11.);
    test_median!(u128_odd: u128 as [12, 17, 11, 8, 9] => 11);
    test_median!(u64_odd: u64 as [12, 17, 11, 8, 9] => 11);
    test_median!(u32_odd: u32 as [12, 17, 11, 8, 9] => 11);
    test_median!(u16_odd: u16 as [12, 17, 11, 8, 9] => 11);
    test_median!(u8_odd: u8 as [12, 17, 11, 8, 9] => 11);
    test_median!(usize_odd: usize as [12, 17, 11, 8, 9] => 11);
    test_median!(i128_odd: i128 as [12, 17, 11, 8, 9] => 11);
    test_median!(i64_odd: i64 as [12, 17, 11, 8, 9] => 11);
    test_median!(i32_odd: i32 as [12, 17, 11, 8, 9] => 11);
    test_median!(i16_odd: i16 as [12, 17, 11, 8, 9] => 11);
    test_median!(i8_odd: i8 as [12, 17, 11, 8, 9] => 11);
    test_median!(isize_odd: isize as [12, 17, 11, 8, 9] => 11);

    test_median!(f64_even: f64 as [12., 17., 8., 9.] => 10.5);
    test_median!(f32_even: f32 as [12., 17., 8., 9.] => 10.5);
    test_median!(u128_even: u128 as [12, 17, 8, 9] => 10);
    test_median!(u64_even: u64 as [12, 17, 8, 9] => 10);
    test_median!(u32_even: u32 as [12, 17, 8, 9] => 10);
    test_median!(u16_even: u16 as [12, 17, 8, 9] => 10);
    test_median!(u8_even: u8 as [12, 17, 8, 9] => 10);
    test_median!(usize_even: usize as [12, 17, 8, 9] => 10);
    test_median!(i128_even: i128 as [12, 17, 8, 9] => 10);
    test_median!(i64_even: i64 as [12, 17, 8, 9] => 10);
    test_median!(i32_even: i32 as [12, 17, 8, 9] => 10);
    test_median!(i16_even: i16 as [12, 17, 8, 9] => 10);
    test_median!(i8_even: i8 as [12, 17, 8, 9] => 10);
    test_median!(isize_even: isize as [12, 17, 8, 9] => 10);

    test_median!(f64_with_inf: f64 as [12., f64::INFINITY, 11., 8., 9.] => 11.);
    test_median!(f64_with_neg_inf: f64 as [12., 16., 11., f64::NEG_INFINITY, 9.] => 11.);
    test_median!(f64_with_nan: f64 as [12., f64::NAN, 16., 11., 8., 9.] => 11.);
    test_median!(f32_with_inf: f32 as [12., f32::INFINITY, 11., 8., 9.] => 11.);
    test_median!(f32_with_neg_inf: f32 as [12., 16., 11., f32::NEG_INFINITY, 9.] => 11.);
    test_median!(f32_with_nan: f32 as [12., f32::NAN, 16., 11., 8., 9.] => 11.);
}