ferray-strings 0.2.11

String operations on character arrays for ferray
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

// ferray-strings: Miscellaneous string operations
//
// str_len, swapcase, and elementwise comparison functions.

use ferray_core::Array;
use ferray_core::dimension::Dimension;
use ferray_core::error::FerrayResult;

use crate::string_array::StringArray;

/// Return the length of each string element. Matches
/// `numpy.strings.str_len` (#518).
pub fn str_len<D: Dimension>(a: &StringArray<D>) -> FerrayResult<Array<u64, D>> {
    let data: Vec<u64> = a.iter().map(|s| s.len() as u64).collect();
    Array::from_vec(a.dim().clone(), data)
}

/// Swap the case of each character in every element. Matches
/// `numpy.strings.swapcase` (#515).
pub fn swapcase<D: Dimension>(a: &StringArray<D>) -> FerrayResult<StringArray<D>> {
    a.map(|s| {
        s.chars()
            .map(|c| {
                if c.is_uppercase() {
                    c.to_lowercase().collect::<String>()
                } else if c.is_lowercase() {
                    c.to_uppercase().collect::<String>()
                } else {
                    c.to_string()
                }
            })
            .collect()
    })
}

// ---------------------------------------------------------------------------
// Elementwise string comparison (#516)
// ---------------------------------------------------------------------------

/// Elementwise string equality. Both arrays must have the same shape.
pub fn equal<D: Dimension>(a: &StringArray<D>, b: &StringArray<D>) -> FerrayResult<Array<bool, D>> {
    let data: Vec<bool> = a.iter().zip(b.iter()).map(|(x, y)| x == y).collect();
    Array::from_vec(a.dim().clone(), data)
}

/// Elementwise string inequality.
pub fn not_equal<D: Dimension>(
    a: &StringArray<D>,
    b: &StringArray<D>,
) -> FerrayResult<Array<bool, D>> {
    let data: Vec<bool> = a.iter().zip(b.iter()).map(|(x, y)| x != y).collect();
    Array::from_vec(a.dim().clone(), data)
}

/// Elementwise lexicographic less-than.
pub fn less<D: Dimension>(a: &StringArray<D>, b: &StringArray<D>) -> FerrayResult<Array<bool, D>> {
    let data: Vec<bool> = a.iter().zip(b.iter()).map(|(x, y)| x < y).collect();
    Array::from_vec(a.dim().clone(), data)
}

/// Elementwise lexicographic greater-than.
pub fn greater<D: Dimension>(
    a: &StringArray<D>,
    b: &StringArray<D>,
) -> FerrayResult<Array<bool, D>> {
    let data: Vec<bool> = a.iter().zip(b.iter()).map(|(x, y)| x > y).collect();
    Array::from_vec(a.dim().clone(), data)
}

/// Elementwise lexicographic less-or-equal.
pub fn less_equal<D: Dimension>(
    a: &StringArray<D>,
    b: &StringArray<D>,
) -> FerrayResult<Array<bool, D>> {
    let data: Vec<bool> = a.iter().zip(b.iter()).map(|(x, y)| x <= y).collect();
    Array::from_vec(a.dim().clone(), data)
}

/// Elementwise lexicographic greater-or-equal.
pub fn greater_equal<D: Dimension>(
    a: &StringArray<D>,
    b: &StringArray<D>,
) -> FerrayResult<Array<bool, D>> {
    let data: Vec<bool> = a.iter().zip(b.iter()).map(|(x, y)| x >= y).collect();
    Array::from_vec(a.dim().clone(), data)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::string_array::array;

    #[test]
    fn test_str_len() {
        let a = array(&["hello", "", "abc", "hi"]).unwrap();
        let r = str_len(&a).unwrap();
        assert_eq!(r.as_slice().unwrap(), &[5, 0, 3, 2]);
    }

    #[test]
    fn test_swapcase() {
        let a = array(&["Hello World", "ABC", "abc", "123"]).unwrap();
        let r = swapcase(&a).unwrap();
        assert_eq!(r.as_slice(), &["hELLO wORLD", "abc", "ABC", "123"]);
    }

    #[test]
    fn test_equal() {
        let a = array(&["abc", "def", "ghi"]).unwrap();
        let b = array(&["abc", "xyz", "ghi"]).unwrap();
        let r = equal(&a, &b).unwrap();
        assert_eq!(r.as_slice().unwrap(), &[true, false, true]);
    }

    #[test]
    fn test_less() {
        let a = array(&["abc", "xyz"]).unwrap();
        let b = array(&["abd", "abc"]).unwrap();
        let r = less(&a, &b).unwrap();
        assert_eq!(r.as_slice().unwrap(), &[true, false]);
    }

    #[test]
    fn test_greater() {
        let a = array(&["xyz", "abc"]).unwrap();
        let b = array(&["abc", "xyz"]).unwrap();
        let r = greater(&a, &b).unwrap();
        assert_eq!(r.as_slice().unwrap(), &[true, false]);
    }
}