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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/itertools/src/group_map.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/itertools/src/group_map.rs')
-rw-r--r-- | third_party/rust/itertools/src/group_map.rs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/third_party/rust/itertools/src/group_map.rs b/third_party/rust/itertools/src/group_map.rs new file mode 100644 index 0000000000..a2d0ebb2ab --- /dev/null +++ b/third_party/rust/itertools/src/group_map.rs @@ -0,0 +1,32 @@ +#![cfg(feature = "use_std")] + +use std::collections::HashMap; +use std::hash::Hash; +use std::iter::Iterator; + +/// Return a `HashMap` of keys mapped to a list of their corresponding values. +/// +/// See [`.into_group_map()`](crate::Itertools::into_group_map) +/// for more information. +pub fn into_group_map<I, K, V>(iter: I) -> HashMap<K, Vec<V>> + where I: Iterator<Item=(K, V)>, + K: Hash + Eq, +{ + let mut lookup = HashMap::new(); + + iter.for_each(|(key, val)| { + lookup.entry(key).or_insert_with(Vec::new).push(val); + }); + + lookup +} + +pub fn into_group_map_by<I, K, V>(iter: I, f: impl Fn(&V) -> K) -> HashMap<K, Vec<V>> + where + I: Iterator<Item=V>, + K: Hash + Eq, +{ + into_group_map( + iter.map(|v| (f(&v), v)) + ) +} |