Jeremy Daer jeremy

We've seen lots of Ruby feature requests about converting an Enumerable to a Hash: to_h, map_hash, map_to, each_with_hash, etc. Let's look at one common, simple case of this.

Building a key/value mapping from a collection of keys is awkward. We commonly see Hash[*collection.map { |element| [element, calculate(element)] }] or collection.each_with_object({}) { |element, hash| hash[element] = calculate(element) }. Both are verbose. They require boilerplate code that's not relevant to the programmer's intent: to associate an enumerable of keys with calculated values.

Ruby has the idea of an association already: a key and value paired together. It's used by Array#assoc to look up a value from a list of pairs and by Hash#assoc to return a key/value pair. Building up a mapping of key/value pairs is associating keys with values.

So! Consider Enumerable#associate which builds a mapping by associating keys with values:

# Associate filenames with URLs. Before:

	# Configure generators to use sequel, haml, and shoulda.
	config.generators do \|g\|
	g.orm :sequel
	g.template_engine :haml
	g.test_framework :shoulda, :fixtures => true
	end

	<table width="100%">
	<tr><td width="50%">
	{% compare_with_last_week_chart metric:'Custom/Objects/Allocated' title:'Object Allocations' value:total_value %}
	</td><td width="50%">
	{% compare_with_last_week_chart metric:'Custom/Objects/Live' title:'Live Objects' value:average_value %}
	</td></tr>
	</table>

	# Dependencies: ruby, git, rubygems

	sudo gem install bundler
	git clone git://github.com/rails/rails.git
	cd rails && gem bundle

	ruby -rvendor/gems/environment railties/bin/rails ../new_app
	cd ../new_app

	# edit Gemfile to use:

	<?xml version="1.0" encoding="UTF-8" ?>
	<schema name="basecamp" version="1.3">
	<types>
	<!-- indexed/stored verbatim -->
	<fieldType name="string" class="solr.StrField" sortMissingLast="true" omitNorms="true" omitTermFreqAndPositions="true"/>

	<!-- "true" or "false" -->
	<fieldType name="boolean" class="solr.BoolField" sortMissingLast="true" omitNorms="true" omitTermFreqAndPositions="true"/>

	<!-- binary data, base64 -->

	#!/usr/bin/env bash
	# https://github.com/elasticsearch/elasticsearch/issues/1357
	set -o verbose

	curl -s -XGET http://localhost:9200/ \|grep -B 1 number

	curl -XDELETE http://localhost:9200/foo

	curl -XPUT http://localhost:9200/foo -d '{
	"mappings": {

	$ curl http://10.11.0.6:9200/migrations/_settings
	{"migrations":{"settings":{"index.number_of_shards":"1","index.auto_expand_replicas":"1-all","index.number_of_replicas":"2"}}}

	$ curl http://10.11.0.6:9200/migrations/_settings?pretty=true
	{
	"migrations" : {
	"settings" : {
	"index.number_of_shards" : "1",
	"index.auto_expand_replicas" : "0-all",
	"index.number_of_replicas" : "0"

	require 'restclient'

	# RestClient logs using << which isn't supported by the Rails logger,
	# so wrap it up with a little proxy object.
	RestClient.log =
	Object.new.tap do \|proxy\|
	def proxy.<<(message)
	Rails.logger.info message
	end
	end

	3572 zzForAction: {
	3573 while (true) {
	3574
	3575 if (zzCurrentPosL < zzEndReadL)
	3576 zzInput = zzBufferL[zzCurrentPosL++];
	3577 else if (zzAtEOF) {
	3578 zzInput = YYEOF;
	3579 break zzForAction;
	3580 }
	3581 else {

	commit 63a12f72df1a7507f7a1923bdaa56b56b876b562
	Author: Jeremy Kemper <[email protected]>
	Date: Fri Sep 14 17:00:46 2012 -0700

	Pass an exception_handler to queue consumers. Don't run jobs in synchronous & test queues; delegate to a consumer.

	diff --git a/activesupport/lib/active_support/queueing.rb b/activesupport/lib/active_support/queueing.rb
	index f397e1c..c4ff8b8 100644
	--- a/activesupport/lib/active_support/queueing.rb
	+++ b/activesupport/lib/active_support/queueing.rb