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





/// pad a string to the left to ``pad`` length with spaces
/// If str.len() is less than pad, then the string is returned verbatim
pub fn left_pad(s: &str, pad: usize) -> String
{
    left_pad_char(s, pad, ' ')
}

/// pad a string to the left to ``pad`` length with ``padchar``
/// If str.len() is less than pad, then the string is returned verbatim
pub fn left_pad_char(s: &str, pad: usize, padchar: char) -> String
{
    let mut out = String::new();

    let len = s.len();
    if pad > len {
        for _ in 0..pad-len {
            out.push(padchar);
        }
    }
    out.push_str(s);

    out
}

#[cfg(test)]
#[test]
fn pad_test() {

    assert_eq!(left_pad("foo", 0), "foo");
    assert_eq!(left_pad("foo", 2), "foo");
    assert_eq!(left_pad_char("bar", 0, 'Y'), "bar");
    assert_eq!(left_pad("foo", 5), "  foo");
    assert_eq!(left_pad_char("foo", 7, 'X'), "XXXXfoo");
    assert_eq!(left_pad_char("bar", 5, '-'), "--bar");
}