[ruby-core:96300] [Ruby master Feature#16428] Add Array#uniq?
From:
duerst@...
Date:
2019-12-18 05:02:43 UTC
List:
ruby-core #96300
Issue #16428 has been updated by duerst (Martin Dst).
I seem to member that many years ago, I made the same proposal, and Nobu created a patch, but unfortunately, I didn't find any traces anymore on this tracker or in my mail.
Anyway, I support this proposal. It's definitely an useful functionality, and it's clearly faster than doing it indirectly via #uniq.
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Feature #16428: Add Array#uniq?
https://bugs.ruby-lang.org/issues/16428#change-83205
* Author: kyanagi (Kouhei Yanagita)
* Status: Open
* Priority: Normal
* Assignee:
* Target version:
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I propose Array#uniq?.
I often need to check if an array have duplicate elements.
This method returns true if no duplicates are found in self, otherwise returns false.
If a block is given, it will use the return value of the block for comparison.
This is equivalent to `array.uniq.size == array.size`, but faster.
```
% ~/tmp/r/bin/ruby -rbenchmark/ips -e 'a = Array.new(100) { rand(1000) }; Benchmark.ips { |x| x.report("uniq") { a.uniq.size == a.size }; x.report("uniq?") { a.uniq? } }'
Warming up --------------------------------------
uniq 25.765k i/100ms
uniq? 76.544k i/100ms
Calculating -------------------------------------
uniq 278.144k (ア 4.1%) i/s - 1.391M in 5.010858s
uniq? 981.868k (ア 5.1%) i/s - 4.975M in 5.081611s
```
I think the name `uniq?` is natural because Array already has `uniq`.
patch: https://github.com/ruby/ruby/pull/2762
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