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Add Hash#key? vs. Hash#keys.include? and Hash#value? vs. Hash#values.include? #154

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Merged
ixti merged 3 commits into from
May 2, 2018
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Add Hash#key? vs. Hash#keys.include? and Hash#value? vs. Hash#values.include? #154

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c27969a
Add Hash#key? vs. Hash#keys.include? and Hash#value? vs. Hash#values.…
JacobEvelyn Apr 27, 2018
68ad9dd
Separate keys and values, and simplify benchmarks
JacobEvelyn May 1, 2018
4b42f95
Remove `Hash#[]` from tests
JacobEvelyn May 2, 2018
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Remove Hash#[] from tests
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@JacobEvelyn
JacobEvelyn committed May 2, 2018
commit 4b42f95e430a7888d341fa44e7bcd62c0cb377ac
18 changes: 7 additions & 11 deletions README.md
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Expand Up @@ -805,25 +805,21 @@ Comparison:
Hash#keys.each: 869262.3 i/s - 1.21x slower
```

#### `Hash#key?` vs. `Hash#[]` vs. `Hash#keys.include?` [code](code/hash/keys-include-vs-\[\]-vs-key.rb)
#### `Hash#key?` instead of `Hash#keys.include?` [code](code/hash/keys-include-vs-\[\]-vs-key.rb)

> `Hash#keys.include?` allocates an array of keys and performs an O(n) search; <br>
> `Hash#key?` performs an O(1) hash lookup without allocating a new array; <br>
> `Hash#[]` performs an O(1) hash lookup as well.
> `Hash#key?` performs an O(1) hash lookup without allocating a new array.

```
$ ruby -v code/hash/keys-include-vs-\[\]-vs-key.rb
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin17]
$ ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin17]

Calculating -------------------------------------
Hash#keys.include? 8.293k (± 6.1%) i/s - 41.964k in 5.083215s
Hash#[] 6.412M (± 3.1%) i/s - 32.160M in 5.020295s
Hash#key? 6.616M (± 5.0%) i/s - 33.178M in 5.030955s
Hash#keys.include? 8.612k (± 2.5%) i/s - 43.248k in 5.024749s
Hash#key? 6.366M (± 5.5%) i/s - 31.715M in 5.002276s

Comparison:
Hash#key?: 6615589.2 i/s
Hash#[]: 6412217.3 i/s - same-ish: difference falls within error
Hash#keys.include?: 8293.2 i/s - 797.71x slower
Hash#key?: 6365855.5 i/s
Hash#keys.include?: 8612.4 i/s - 739.15x slower
```

##### `Hash#value?` instead of `Hash#values.include?` [code](code/hash/values-include-vs-value.rb)
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5 changes: 0 additions & 5 deletions code/hash/keys-include-vs-[]-vs-key.rb → code/hash/keys-include-vs-key.rb
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Expand Up @@ -7,17 +7,12 @@ def key_fast
HASH.key? KEY
end

def key_resolve
!!HASH[KEY]
end

def key_slow
HASH.keys.include? KEY
end

Benchmark.ips do |x|
x.report("Hash#keys.include?") { key_slow }
x.report("Hash#[]") { key_resolve }
x.report("Hash#key?") { key_fast }
x.compare!
end