Trait take_until::TakeUntilExt
source · pub trait TakeUntilExt<P>where
Self: Sized,{
// Required method
fn take_until(self, predicate: P) -> TakeUntil<Self, P>;
}
Expand description
TakeUntilExt is an extension trait for iterators.
It adds the Self::take_until
method.
Required Methods§
sourcefn take_until(self, predicate: P) -> TakeUntil<Self, P>
fn take_until(self, predicate: P) -> TakeUntil<Self, P>
Accepts elements until a predicate is true. Using this iterator is
equivalent to an inclusive Iterator::take_while
with a negated
condition.
Example
Parsing the next base 128 varint from a byte slice.
use take_until::TakeUntilExt;
let varint = &[0b1010_1100u8, 0b0000_0010, 0b1000_0001];
let int: u32 = varint
.iter()
.take_until(|b| (**b & 0b1000_0000) == 0)
.enumerate()
.fold(0, |acc, (i, b)| {
acc | ((*b & 0b0111_1111) as u32) << (i * 7)
});
assert_eq!(300, int);
Take Until vs Take While (from Standard Library)
use take_until::TakeUntilExt;
let items = [1, 2, 3, 4, -5, -6, -7, -8];
let filtered_take_while = items
.into_iter()
.take_while(|x| *x > 0)
.collect::<Vec<i32>>();
let filtered_take_until = items
.into_iter()
.take_until(|x| *x <= 0)
.collect::<Vec<i32>>();
assert_eq!([1, 2, 3, 4], filtered_take_while.as_slice());
assert_eq!([1, 2, 3, 4, -5], filtered_take_until.as_slice());