Struct KeysIterator 

pub struct KeysIterator<'a> { /* private fields */ }

Structure to iterate through key names in KeyedMessage.

Mainly useful to discover what keys are present inside the message.

Implements FallibleIterator providing similar functionality to classic Iterator. FallibleIterator is used because internal ecCodes functions can return internal error in some edge-cases. The usage of FallibleIterator is sligthly different than usage of Iterator, check the documentation for more details.

To discover key contents you need to read_key with name given by the iterator.

Example

 use eccodes::{ProductKind, CodesHandle, KeyedMessage, KeysIteratorFlags};
 use eccodes::{FallibleIterator, FallibleStreamingIterator};
 let file_path = Path::new("./data/iceland.grib");
 let product_kind = ProductKind::GRIB;
  
 let mut handle = CodesHandle::new_from_file(file_path, product_kind)?;
 let current_message = handle.next()?.context("no message")?;
  
 let mut keys_iter = current_message.default_keys_iterator()?;
  
 while let Some(key_name) = keys_iter.next()? {
     println!("{key_name}");
 }

Errors

The next() method will return CodesInternal when internal ecCodes function returns non-zero code.

Trait Implementations

impl<'a> Debug for KeysIterator<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FallibleIterator for KeysIterator<'_>

type Item = String

The type being iterated over.

type Error = CodesError

The error type.

fn next(&mut self) -> Result<Option<Self::Item>, Self::Error>

Advances the iterator and returns the next value.

fn size_hint(&self) -> (usize, Option<usize>)

Returns bounds on the remaining length of the iterator.

fn count(self) -> Result<usize, Self::Error>

where Self: Sized,

Consumes the iterator, returning the number of remaining items.

fn last(self) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized,

Returns the last element of the iterator.

fn nth(&mut self, n: usize) -> Result<Option<Self::Item>, Self::Error>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>

where Self: Sized,

Returns an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<I>(self, it: I) -> Chain<Self, I>

where I: IntoFallibleIterator<Item = Self::Item, Error = Self::Error>, Self: Sized,

Returns an iterator which yields the elements of this iterator followed by another.

fn zip<I>( self, o: I, ) -> Zip<Self, <I as IntoFallibleIterator>::IntoFallibleIter>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>,

Returns an iterator that yields pairs of this iterator’s and another iterator’s values.

fn map<F, B>(self, f: F) -> Map<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Result<B, Self::Error>,

Returns an iterator which applies a fallible transform to the elements of the underlying iterator.

fn for_each<F>(self, f: F) -> Result<(), Self::Error>

where Self: Sized, F: FnMut(Self::Item) -> Result<(), Self::Error>,

Calls a fallible closure on each element of an iterator.

fn filter<F>(self, f: F) -> Filter<Self, F>

where Self: Sized, F: FnMut(&Self::Item) -> Result<bool, Self::Error>,

Returns an iterator which uses a predicate to determine which values should be yielded. The predicate may fail; such failures are passed to the caller.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Result<Option<B>, Self::Error>,

Returns an iterator which both filters and maps. The closure may fail; such failures are passed along to the consumer.

fn enumerate(self) -> Enumerate<Self>

where Self: Sized,

Returns an iterator which yields the current iteration count as well as the value.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Returns an iterator that can peek at the next element without consuming it.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> Result<bool, Self::Error>,

Returns an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> Result<bool, Self::Error>,

Returns an iterator that yields elements based on a predicate.

fn skip(self, n: usize) -> Skip<Self>

where Self: Sized,

Returns an iterator which skips the first n values of this iterator.

fn take(self, n: usize) -> Take<Self>

where Self: Sized,

Returns an iterator that yields only the first n values of this iterator.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>

where Self: Sized, F: FnMut(&mut St, Self::Item) -> Result<Option<B>, Self::Error>,

Returns an iterator which applies a stateful map to values of this iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>

where Self: Sized, U: IntoFallibleIterator<Error = Self::Error>, F: FnMut(Self::Item) -> Result<U, Self::Error>,

Returns an iterator which maps this iterator’s elements to iterators, yielding those iterators’ values.

fn flatten(self) -> Flatten<Self>

where Self: Sized, Self::Item: IntoFallibleIterator<Error = Self::Error>,

Returns an iterator which flattens an iterator of iterators, yielding those iterators’ values.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Returns an iterator which yields this iterator’s elements and ends after the first Ok(None).

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where Self: Sized, F: FnMut(&Self::Item) -> Result<(), Self::Error>,

Returns an iterator which passes each element to a closure before returning it.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Borrow an iterator rather than consuming it.

fn collect<T>(self) -> Result<T, Self::Error>

where T: FromIterator<Self::Item>, Self: Sized,

Transforms the iterator into a collection.

fn partition<B, F>(self, f: F) -> Result<(B, B), Self::Error>

where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> Result<bool, Self::Error>,

Transforms the iterator into two collections, partitioning elements by a closure.

fn fold<B, F>(self, init: B, f: F) -> Result<B, Self::Error>

where Self: Sized, F: FnMut(B, Self::Item) -> Result<B, Self::Error>,

Applies a function over the elements of the iterator, producing a single final value.

fn try_fold<B, E, F>(&mut self, init: B, f: F) -> Result<B, E>

where Self: Sized, E: From<Self::Error>, F: FnMut(B, Self::Item) -> Result<B, E>,

Applies a function over the elements of the iterator, producing a single final value.

fn all<F>(&mut self, f: F) -> Result<bool, Self::Error>

where Self: Sized, F: FnMut(Self::Item) -> Result<bool, Self::Error>,

Determines if all elements of this iterator match a predicate.

fn any<F>(&mut self, f: F) -> Result<bool, Self::Error>

where Self: Sized, F: FnMut(Self::Item) -> Result<bool, Self::Error>,

Determines if any element of this iterator matches a predicate.

fn find<F>(&mut self, f: F) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, F: FnMut(&Self::Item) -> Result<bool, Self::Error>,

Returns the first element of the iterator that matches a predicate.

fn find_map<B, F>(&mut self, f: F) -> Result<Option<B>, Self::Error>

where Self: Sized, F: FnMut(Self::Item) -> Result<Option<B>, Self::Error>,

Applies a function to the elements of the iterator, returning the first non-None result.

fn position<F>(&mut self, f: F) -> Result<Option<usize>, Self::Error>

where Self: Sized, F: FnMut(Self::Item) -> Result<bool, Self::Error>,

Returns the position of the first element of this iterator that matches a predicate. The predicate may fail; such failures are returned to the caller.

fn max(self) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, Self::Item: Ord,

Returns the maximal element of the iterator.

fn max_by_key<B, F>(self, f: F) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, B: Ord, F: FnMut(&Self::Item) -> Result<B, Self::Error>,

Returns the element of the iterator which gives the maximum value from the function.

fn max_by<F>(self, f: F) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Result<Ordering, Self::Error>,

Returns the element that gives the maximum value with respect to the function.

fn min(self) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, Self::Item: Ord,

Returns the minimal element of the iterator.

fn min_by_key<B, F>(self, f: F) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, B: Ord, F: FnMut(&Self::Item) -> Result<B, Self::Error>,

Returns the element of the iterator which gives the minimum value from the function.

fn min_by<F>(self, f: F) -> Result<Option<Self::Item>, Self::Error>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Result<Ordering, Self::Error>,

Returns the element that gives the minimum value with respect to the function.

fn unzip<A, B, FromA, FromB>(self) -> Result<(FromA, FromB), Self::Error>

where Self: Sized + FallibleIterator<Item = (A, B)>, FromA: Default + Extend<A>, FromB: Default + Extend<B>,

Converts an iterator of pairs into a pair of containers.

fn cloned<'a, T>(self) -> Cloned<Self>

where Self: Sized + FallibleIterator<Item = &'a T>, T: 'a + Clone,

Returns an iterator which clones all of its elements.

fn cmp<I>(self, other: I) -> Result<Ordering, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Item = Self::Item, Error = Self::Error>, Self::Item: Ord,

Lexicographically compares the elements of this iterator to that of another.

fn partial_cmp<I>(self, other: I) -> Result<Option<Ordering>, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialOrd<<I as IntoFallibleIterator>::Item>,

Lexicographically compares the elements of this iterator to that of another.

fn eq<I>(self, other: I) -> Result<bool, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialEq<<I as IntoFallibleIterator>::Item>,

Determines if the elements of this iterator are equal to those of another.

fn ne<I>(self, other: I) -> Result<bool, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialEq<<I as IntoFallibleIterator>::Item>,

Determines if the elements of this iterator are not equal to those of another.

fn lt<I>(self, other: I) -> Result<bool, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialOrd<<I as IntoFallibleIterator>::Item>,

Determines if the elements of this iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> Result<bool, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialOrd<<I as IntoFallibleIterator>::Item>,

Determines if the elements of this iterator are lexicographically less than or equal to those of another.

fn gt<I>(self, other: I) -> Result<bool, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialOrd<<I as IntoFallibleIterator>::Item>,

Determines if the elements of this iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> Result<bool, Self::Error>

where Self: Sized, I: IntoFallibleIterator<Error = Self::Error>, Self::Item: PartialOrd<<I as IntoFallibleIterator>::Item>,

Determines if the elements of this iterator are lexicographically greater than or equal to those of another.

fn iterator(self) -> Iterator<Self>

where Self: Sized,

Returns a normal (non-fallible) iterator over Result<Item, Error>.

fn map_err<B, F>(self, f: F) -> MapErr<Self, F>

where F: FnMut(Self::Error) -> B, Self: Sized,

Returns an iterator which applies a transform to the errors of the underlying iterator.

fn unwrap<T>(self) -> Unwrap<Self>

where Self: Sized + FallibleIterator<Item = T>, Self::Error: Debug,

Returns an iterator which unwraps all of its elements.