pick
Returns a copy of a Map with only the given keys.
Map<K, V> pick<K, V>(Iterable<K> keysToPick, Map<K, V> map)
Lecture
pick is omit's mirror: instead of listing what
to remove, you list what to keep. Requested keys that aren't present in
the source map are simply absent from the result — pick
does not insert them with a null placeholder, so the
result's key set can be smaller than keysToPick.
Reach for it whenever you want a narrow "view" of a larger map: a public API response derived from an internal record, a summary row derived from a full one, and so on.
Demo 1 · Basics
Demo 2 · Slimming a whole list
Try it yourself
Exercise: use pick to keep only 'id' and 'email' from profile.