Function malachite_base::vecs::vec_pad_left

source · 
pub fn vec_pad_left<T: Clone>(xs: &mut Vec<T>, pad_size: usize, pad_value: T)
Expand description

Inserts several copies of a value at the left (beginning) of a Vec.

Using this function is more efficient than inserting the values one by one.

Worst-case complexity

$T(n) = O(n + m)$

$M(n) = O(n + m)$

where $T$ is time, $M$ is additional memory, $n$ = xs.len() before the function is called, and $m$ = pad_size.

Examples

use malachite_base::vecs::vec_pad_left;

let mut xs = vec![1, 2, 3];
vec_pad_left::<u32>(&mut xs, 5, 10);
assert_eq!(xs, [10, 10, 10, 10, 10, 1, 2, 3]);
Examples found in repository?
src/num/conversion/string/to_string.rs (line 300)
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fn to_string_base_signed<U: Digits<u8>, S: Copy + Eq + Ord + UnsignedAbs<Output = U> + Zero>(
    x: &S,
    base: u8,
) -> String {
    assert!((2..=36).contains(&base), "base out of range");
    if *x == S::ZERO {
        "0".to_string()
    } else {
        let mut digits = x.unsigned_abs().to_digits_desc(&u8::wrapping_from(base));
        for digit in &mut digits {
            *digit = digit_to_display_byte_lower(*digit).unwrap();
        }
        if *x < S::ZERO {
            vec_pad_left(&mut digits, 1, b'-');
        }
        String::from_utf8(digits).unwrap()
    }
}

fn to_string_base_upper_signed<
    U: Digits<u8>,
    S: Copy + Eq + Ord + UnsignedAbs<Output = U> + Zero,
>(
    x: &S,
    base: u8,
) -> String {
    assert!((2..=36).contains(&base), "base out of range");
    if *x == S::ZERO {
        "0".to_string()
    } else {
        let mut digits = x.unsigned_abs().to_digits_desc(&base);
        for digit in &mut digits {
            *digit = digit_to_display_byte_upper(*digit).unwrap();
        }
        if *x < S::ZERO {
            vec_pad_left(&mut digits, 1, b'-');
        }
        String::from_utf8(digits).unwrap()
    }
}