From 9be00e7f369e9f6fdcce246d4d3b8b74e4e2e4df Mon Sep 17 00:00:00 2001
From: Ted Johansson <drenmi@gmail.com>
Date: Mon, 11 Jan 2016 18:34:58 +0800
Subject: [PATCH 1/2] Add benchmark for Array#new vs. Fixnum#times + map

When you need to map the result of a block invoked a fixed amount
of times, you have an option between:

```
Array.new(n) { ... }
```

and:

```
n.times.map { ... }
```

The latter one is about 60% slower.
---
 README.md                                   | 16 ++++++++++++++++
 code/array/array-new-vs-fixnum-times-map.rb | 17 +++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 code/array/array-new-vs-fixnum-times-map.rb

diff --git a/README.md b/README.md
index b1f393f..c172f65 100644
--- a/README.md
+++ b/README.md
@@ -382,6 +382,22 @@ Comparison:
         Array#insert:        0.2 i/s - 262.56x slower
 ```
 
+##### `Array#new` vs `Fixnum#times + map` [code](code/array/array-new-vs-fixnum-times-map.rb)
+
+```
+ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15]
+Calculating -------------------------------------
+           Array#new    63.875k i/100ms
+  Fixnum#times + map    48.010k i/100ms
+-------------------------------------------------
+           Array#new      1.070M (± 2.2%) i/s -      5.365M
+  Fixnum#times + map    678.097k (± 2.7%) i/s -      3.409M
+
+Comparison:
+           Array#new:  1069837.0 i/s
+  Fixnum#times + map:   678097.4 i/s - 1.58x slower
+```
+
 ### Enumerable
 
 ##### `Enumerable#each + push` vs `Enumerable#map` [code](code/enumerable/each-push-vs-map.rb)
diff --git a/code/array/array-new-vs-fixnum-times-map.rb b/code/array/array-new-vs-fixnum-times-map.rb
new file mode 100644
index 0000000..fcd7260
--- /dev/null
+++ b/code/array/array-new-vs-fixnum-times-map.rb
@@ -0,0 +1,17 @@
+require "benchmark/ips"
+
+ELEMENTS = 9
+
+def fast
+  Array.new(ELEMENTS) { |i| i }
+end
+
+def slow
+  ELEMENTS.times.map { |i| i }
+end
+
+Benchmark.ips do |x|
+  x.report("Array#new") { fast }
+  x.report("Fixnum#times + map") { slow }
+  x.compare!
+end

From bdfed07e71883444bbde0c34b3578edf80e34081 Mon Sep 17 00:00:00 2001
From: Ted Johansson <drenmi@gmail.com>
Date: Tue, 12 Jan 2016 11:59:22 +0800
Subject: [PATCH 2/2] Add link to benchmark PR in README

As suggested by @deniskorobicyn, adding a link from the `README.md`
to the PR, which has more information on performance characteristics.
---
 README.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/README.md b/README.md
index c172f65..dba76ed 100644
--- a/README.md
+++ b/README.md
@@ -384,6 +384,9 @@ Comparison:
 
 ##### `Array#new` vs `Fixnum#times + map` [code](code/array/array-new-vs-fixnum-times-map.rb)
 
+Typical slowdown is 40-60% depending on the size of the array. See the corresponding
+[pull request](https://github.com/JuanitoFatas/fast-ruby/pull/91/) for performance characteristics.
+
 ```
 ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15]
 Calculating -------------------------------------