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Add .toMap extensions for tuples/pairs and key+value records #359

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Add .toMap extensions for tuples/pairs and key+value records #359

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12 changes: 12 additions & 0 deletions lib/src/iterable_extensions.dart
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Expand Up @@ -914,6 +914,18 @@ extension IterableIterableExtension<T> on Iterable<Iterable<T>> {
};
}

/// Extensions that apply to iterables of tuples/pairs (records with two unnamed elements).
extension IterableTupleExtension<T1, T2> on Iterable<(T1, T2)> {
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@lrhn lrhn Sep 13, 2024 •
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I'm not keen on just using a positional pair as the representation of a key/value pair.
I'd use a type like ({T1 key, T2 value}) instead. I can see that there is a version below that does that, so I would just drop this one.

It does get a little more verbose if you don't want to use key and value as the names for the key and value.
And if you do have a list of pairs, then having to do .map((p) => (key: p.$1, value: p.$2)) does feel unnecessary.

(Maps are not sets of pairs. Now that we have records, Set<(...,...)>s are sets of pairs!)

/// Returns a map from the first element of each tuple to the second element.
Map<T1, T2> get toMap => {for (final element in this) element.$1: element.$2};
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@lrhn lrhn Sep 13, 2024 •
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(Just as style comments, not endorsing the functionality:
toX functionality like toMap() is usually a method, not a getter.
The for loop can destructure: {for (var (key, value) in this) key: value}.
This package doesn't use final for local variables.
I'd use "Creates" instead of "Returns" in the comment. Never start a DocComment with "Returns".)

}

extension IterableKeyValueExtension<T1, T2> on Iterable<({T1 key, T2 value})> {
/// Returns a map from the key of each element to the value of that element.
Map<T1, T2> get toMap =>
{for (final element in this) element.key: element.value};
}

/// Extensions that apply to iterables of [Comparable] elements.
///
/// These operations can assume that the elements have a natural ordering,
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