MAPREDUCE Elite - Revision history

40166222: /* Introducing the elite database */

2018-10-17T13:48:17Z

Introducing the elite database

← Older revision		Revision as of 13:48, 17 October 2018
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	_id, allegiance, faction, government, name, population, primary_economy, security, state, stations, updated_at, x, y, z		_id, allegiance, faction, government, name, population, primary_economy, security, state, stations, updated_at, x, y, z
	systems.stations:		systems.stations:
	allegiance, distance_to_star, economies, export_commodities,has_blackmarket, has_commodities, has_rearm, has_repair,		_id, allegiance, distance_to_star, economies, export_commodities,has_blackmarket, has_commodities, has_rearm, has_repair,
	has_shipyard, has_outfitting, faction, government, listings, max_landing_pad, name, state, type, updated_at		has_shipyard, has_outfitting, faction, government, listings, max_landing_pad, name, state, type, updated_at
	systems.stations.listings:		systems.stations.listings:
	buy_price, collected_at, demand, commodity, sell_price, supply, update_count		_id, buy_price, collected_at, demand, commodity, sell_price, supply, update_count
	</pre>		</pre>
	Read more about the structure here: [[Elite Document Structure]]		Read more about the structure here: [[Elite Document Structure]]
	<br/><br/>		<br/><br/>

	==Questions==		==Questions==
	<div class="q" data-lang="mongo" data-switches='elite'>The <code>commodities</code> collection contains the <code>name</code> and <code>average_price</code> of each commodity.<br/>		<div class="q" data-lang="mongo" data-switches='elite'>The <code>commodities</code> collection contains the <code>name</code> and <code>average_price</code> of each commodity.<br/>

40166222 at 14:58, 22 June 2018

2018-06-22T14:58:31Z

← Older revision		Revision as of 14:58, 22 June 2018
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	<pre class="ans"><nowiki>db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</nowiki></pre>		<pre class="ans"><nowiki>db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</nowiki></pre>
	</div>		</div>
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40166222 at 19:28, 21 June 2018

2018-06-21T19:28:56Z

← Older revision		Revision as of 19:28, 21 June 2018
Line 24:		Line 24:
	db.commodities.mapReduce(		db.commodities.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1, 1);
	},		},
	function(k,v){		function(k, v){
	return Array.sum(v);		return Array.sum(v);
	},		},
	{out:{inline:1}}		{out: {inline: 1}}
	)		);</nowiki></pre>
	</nowiki></pre>		<pre class="ans"><nowiki>db.commodities.mapReduce(function(){emit(this.category,this.average_price);},function(k,v){return Math.round(Array.sum(v)/v.length);},{out:{inline:1}});</nowiki></pre>
	<pre class="ans"><nowiki>
	db.commodities.mapReduce(function(){emit(this.category,this.average_price);},function(k,v){return Math.round(Array.sum(v)/v.length);},{out:{inline:1}})
	</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>Each system has an <code>allegiance</code>. There are three main factions: <b>The Federation</b>, <b>The Empire</b>, and <b>The Alliance</b>.<br/>		<div class="q" data-lang="mongo" data-switches='elite'>Each system has an <code>allegiance</code>. There are three main factions: <b>The Federation</b>, <b>The Empire</b>, and <b>The Alliance</b>.<br/>
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	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1, 1);
	},		},
	function(k,v){		function(k, v){
	return Array.sum(v);		return Array.sum(v);
	},		},
	{out:{inline:1}}		{out: {inline: 1}}
	)		);</nowiki></pre>
	</nowiki></pre>		<pre class="ans"><nowiki>db.systems.mapReduce(function(){if (this.allegiance!=null){emit(this.allegiance,1);}},function(k,v){return Array.sum(v);},{out:{inline:1}});</nowiki></pre>
	<pre class="ans"><nowiki>
	db.systems.mapReduce(function(){if (this.allegiance!=null){emit(this.allegiance,1);}},function(k,v){return Array.sum(v);},{out:{inline:1}})
	</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>		<div class="q" data-lang="mongo" data-switches='elite'>
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	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1, 1);
	},		},
	function(k,v){		function(k, v){
	return Array.sum(v);		return Array.sum(v);
	},		},
	{out:{inline:1}}		{out: {inline: 1}}
	)		);</nowiki></pre>
	</pre>		<pre class="ans"><nowiki>db.systems.mapReduce(function(){if(!isNaN(this.population)&&this.allegiance!=null&&this.allegiance!="Independent"&&this.allegiance!="Anarchy"){emit(this.allegiance,this.population);}},function(k,v){return Array.sum(v);},{out:{inline:1}});</nowiki></pre>
	<pre class="ans"><nowiki>
	db.systems.mapReduce(function(){if(!isNaN(this.population)&&this.allegiance!=null&&this.allegiance!="Independent"&&this.allegiance!="Anarchy"){emit(this.allegiance,this.population);}},function(k,v){return Array.sum(v);},{out:{inline:1}})
	</nowiki></pre>
	</div>		</div>

Line 85:		Line 76:
	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1, 1);
	},		},
	function(k,v){		function(k, v){
	return Array.sum(v);		return Array.sum(v);
	},		},
	{out:{inline:1}}		{out: {inline: 1}}
	)		);</nowiki></pre>
	</nowiki></pre>		<pre class="ans"><nowiki>db.systems.mapReduce(function(){if(this.stations)for(let i=0;i<this.stations.length;i++){let t=this.stations[i];if(t.listings&&t.allegiance)for(let s=0;s<t.listings.length;s++){let n=t.listings[s];"Hydrogen Fuel"===n.commodity&&emit(t.allegiance,n.supply)}}},function(i,t){return Array.sum(t)},{out:{inline:1},limit:5e3});</nowiki></pre>
	<pre class="ans"><nowiki>
	db.systems.mapReduce(function(){if(this.stations)for(let i=0;i<this.stations.length;i++){let t=this.stations[i];if(t.listings&&t.allegiance)for(let s=0;s<t.listings.length;s++){let n=t.listings[s];"Hydrogen Fuel"===n.commodity&&emit(t.allegiance,n.supply)}}},function(i,t){return Array.sum(t)},{out:{inline:1},limit:5e3});
	</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>A <code>power_control_faction</code> or <b>Power</b> is an individual or organisation who is in control of a system.<br/>		<div class="q" data-lang="mongo" data-switches='elite'>A <code>power_control_faction</code> or <b>Power</b> is an individual or organisation who is in control of a system.<br/>
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	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1, 1);
	},		},
	function(k,v){		function(k,v){
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	out: {inline: 1}		out: {inline: 1}
	}		}
	)		);</nowiki></pre>
	</nowiki></pre>		<pre class="ans"><nowiki>db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(_,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</nowiki></pre>
	<pre class="ans"><nowiki>
	db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(_,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});
	</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:		<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:
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	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1, 1);
	},		},
	function(k,v){		function(k, v){
	return Array.sum(v);		return Array.sum(v);
	},		},
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	out: {inline: 1}		out: {inline: 1}
	}		}
	)		);</nowiki></pre>
	</nowiki></pre>		<pre class="ans"><nowiki>db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</nowiki></pre>
	<pre class="ans"><nowiki>
	db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});
	</nowiki></pre>
	</div>		</div>

40166222 at 13:31, 15 June 2018

2018-06-15T13:31:32Z

← Older revision		Revision as of 13:31, 15 June 2018
Line 21:		Line 21:
	There are 99 unique commodities and 15 categories.		There are 99 unique commodities and 15 categories.
	<p class="strong">Find the average price of each category, round to the nearest whole number.</p>		<p class="strong">Find the average price of each category, round to the nearest whole number.</p>
	<pre class="def">		<pre class="def"><nowiki>
	db.commodities.mapReduce(		db.commodities.mapReduce(
	function(){		function(){
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	{out:{inline:1}}		{out:{inline:1}}
	)		)
	</pre>		</nowiki></pre>
	<pre class="ans">db.commodities.mapReduce(function(){emit(this.category,this.average_price);},function(k,v){return Math.round(Array.sum(v)/v.length);},{out:{inline:1}})</pre>		<pre class="ans"><nowiki>
			db.commodities.mapReduce(function(){emit(this.category,this.average_price);},function(k,v){return Math.round(Array.sum(v)/v.length);},{out:{inline:1}})
			</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>Each system has an <code>allegiance</code>. There are three main factions: <b>The Federation</b>, <b>The Empire</b>, and <b>The Alliance</b>.<br/>		<div class="q" data-lang="mongo" data-switches='elite'>Each system has an <code>allegiance</code>. There are three main factions: <b>The Federation</b>, <b>The Empire</b>, and <b>The Alliance</b>.<br/>
	<p>Non-populated systems without stations do not have an allegiance, and should be ignored.</p>		<p>Non-populated systems without stations do not have an allegiance, and should be ignored.</p>
	<p class="strong">Show the amount of systems following each type of allegiance.</p>		<p class="strong">Show the amount of systems following each type of allegiance.</p>
	<pre class="def">		<pre class="def"><nowiki>
	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
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	{out:{inline:1}}		{out:{inline:1}}
	)		)
	</pre>		</nowiki></pre>
	<pre class="ans">db.systems.mapReduce(function(){if (this.allegiance!=null){emit(this.allegiance,1);}},function(k,v){return Array.sum(v);},{out:{inline:1}})</pre></div>		<pre class="ans"><nowiki>
			db.systems.mapReduce(function(){if (this.allegiance!=null){emit(this.allegiance,1);}},function(k,v){return Array.sum(v);},{out:{inline:1}})
			</nowiki></pre>
			</div>
	<div class="q" data-lang="mongo" data-switches='elite'>		<div class="q" data-lang="mongo" data-switches='elite'>
	<p class="strong">What are the populations of the three main factions?</p>		<p class="strong">What are the populations of the three main factions?</p>
	<div class="hint" title="Three main factions">["Alliance","Federation","Empire"]</div>		<div class="hint" title="Three main factions">["Alliance","Federation","Empire"]</div>
	<div class="hint" title="NaN?">Some systems are not populated and will have '''null''' population fields, make sure to exclude them using <code>!isNaN()</code>.</div>		<div class="hint" title="NaN?">Some systems are not populated and will have '''null''' population fields, make sure to exclude them using <code>!isNaN()</code>.</div>
	<pre class="def">		<pre class="def"><nowiki>
	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
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	)		)
	</pre>		</pre>
	<pre class="ans">db.systems.mapReduce(function(){if(!isNaN(this.population)&&this.allegiance!=null&&this.allegiance!="Independent"&&this.allegiance!="Anarchy"){emit(this.allegiance,this.population);}},function(k,v){return Array.sum(v);},{out:{inline:1}})</pre>		<pre class="ans"><nowiki>
			db.systems.mapReduce(function(){if(!isNaN(this.population)&&this.allegiance!=null&&this.allegiance!="Independent"&&this.allegiance!="Anarchy"){emit(this.allegiance,this.population);}},function(k,v){return Array.sum(v);},{out:{inline:1}})
			</nowiki></pre>
	</div>		</div>

	==Harder Questions==		==Harder Questions==
	<div class="q" data-lang="mongo" data-switches='elite'>How much Hydrogen Fuel is owned by each faction? Limit your query to the first 5000 stations.		<div class="q" data-lang="mongo" data-switches='elite'>
			<p class="strong">
			How much Hydrogen Fuel is owned by each faction? Limit your query to the first 5000 stations.
			</p>
	<div class="hint" title="hint">		<div class="hint" title="hint">
	The amount of stations in a system <b>and</b> the amount of listings to a station aren't fixed. <code>query</code> can be used to ensure that they exist.		The amount of stations in a system <b>and</b> the amount of listings to a station aren't fixed. <code>query</code> can be used to ensure that they exist.
	</div>		</div>
	<pre class="def">		<pre class="def"><nowiki>
	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
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	{out:{inline:1}}		{out:{inline:1}}
	)		)
	</pre>		</nowiki></pre>
	<pre class="ans">db.systems.mapReduce(function(){if(this.stations)for(let i=0;i<this.stations.length;i++){let t=this.stations[i];if(t.listings&&t.allegiance)for(let s=0;s<t.listings.length;s++){let n=t.listings[s];"Hydrogen Fuel"===n.commodity&&emit(t.allegiance,n.supply)}}},function(i,t){return Array.sum(t)},{out:{inline:1},limit:5e3});</pre>		<pre class="ans"><nowiki>
			db.systems.mapReduce(function(){if(this.stations)for(let i=0;i<this.stations.length;i++){let t=this.stations[i];if(t.listings&&t.allegiance)for(let s=0;s<t.listings.length;s++){let n=t.listings[s];"Hydrogen Fuel"===n.commodity&&emit(t.allegiance,n.supply)}}},function(i,t){return Array.sum(t)},{out:{inline:1},limit:5e3});
			</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>A <code>power_control_faction</code> or <b>Power</b> is an individual or organisation who is in control of a system.<br/>		<div class="q" data-lang="mongo" data-switches='elite'>A <code>power_control_faction</code> or <b>Power</b> is an individual or organisation who is in control of a system.<br/>
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	</div>		</div>
	<p class="strong">Show the allegiance of each of the power's systems</p>		<p class="strong">Show the allegiance of each of the power's systems</p>
	<pre class="def">		<pre class="def"><nowiki>
	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
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	}		}
	)		)
	</pre>		</nowiki></pre>
	<pre class="ans">db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</pre>		<pre class="ans"><nowiki>
			db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(_,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});
			</nowiki></pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:		<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:
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	}		}
	</pre></div>		</pre></div>
	<pre class="def">		<pre class="def"><nowiki>
	db.systems.mapReduce(		db.systems.mapReduce(
	function(){		function(){
Line 140:		Line 154:
	}		}
	)		)
	</pre>		</nowiki></pre>
	<pre class="ans">db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</pre>		<pre class="ans"><nowiki>
			db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});
			</nowiki></pre>
	</div>		</div>

40166222: Massively simplify answers for Q5/6

2018-03-23T14:11:29Z

Massively simplify answers for Q5/6

← Older revision		Revision as of 14:11, 23 March 2018
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	)		)
	</pre>		</pre>
	<pre class="ans">		<pre class="ans">db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</pre>
	db.systems.mapReduce(function(){~~switch(this.allegiance){case "Alliance":~~emit(this.power_control_faction,{~~Alliance~~:1~~,Anarchy:0,Empire:0,Federation:0,Independent:0~~});~~break;case "Anarchy":emit~~(~~this.power_control_faction~~,{Alliance:0,Anarchy~~:1,Empire:0,Federation~~:0,~~Independent:0});break;case~~ "Empire"~~:emit(this.power_control_faction,{Alliance:0,Anarchy~~:0,~~Empire:1,Federation:0,Independent:0});break;case~~ "Federation"~~:emit(this.power_control_faction,{Alliance:0,Anarchy:0,Empire~~:0,~~Federation:1,Independent:0});break;case~~ "Independent"~~:emit(this.power_control_faction,{Alliance~~:0~~,Anarchy:0,Empire:0,Federation:0,Independent:1~~}~~);break;}},function(k,v){let a=v[0]~~;for(let i=1;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance;a.Anarchy+=b.Anarchy;a.Empire+=b.Empire;a.Federation+=b.Federation;a.Independent+=b.Independent;}return a;},{out:{"inline":1},query:{"power_control_faction":{"$exists":1}}})
	</pre>
	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:		<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:
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	)		)
	</pre>		</pre>
	<pre class="ans">		<pre class="ans">db.systems.mapReduce(function(){emit(this.power_control_faction,{[this.allegiance]:1});},function(k,v){let a={"Alliance":0,"Anarchy":0,"Empire":0,"Federation":0,"Independent":0};for(let i=0;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance\|\|0;a.Anarchy+=b.Anarchy\|\|0;a.Empire+=b.Empire\|\|0;a.Federation+=b.Federation\|\|0;a.Independent+=b.Independent\|\|0;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}},sort:{"_id":1}});</pre>
	db.systems.mapReduce(function(){~~switch(this.allegiance){case "Alliance":~~emit(this.power_control_faction,{~~Alliance~~:1~~,Anarchy:0,Empire:0,Federation:0,Independent:0~~});~~break;case "Anarchy":emit~~(~~this.power_control_faction~~,{Alliance:0,Anarchy~~:1,Empire:0,Federation~~:0,~~Independent:0});break;case~~ "Empire"~~:emit(this.power_control_faction,{Alliance:0,Anarchy~~:0,~~Empire:1,Federation:0,Independent:0});break;case~~ "Federation"~~:emit(this.power_control_faction,{Alliance:0,Anarchy:0,Empire~~:0,~~Federation:1,Independent:0});break;case~~ "Independent"~~:emit(this.power_control_faction,{Alliance~~:0~~,Anarchy:0,Empire:0,Federation:0,Independent:1~~}~~);break;}},function(k,v){let a=v[0]~~; for(let i=1;i<v.length;i++){let b=v[i];a.Alliance+=b.Alliance;a.Anarchy+=b.Anarchy;a.Empire+=b.Empire;a.Federation+=b.Federation;a.Independent+=b.Independent;}return a;},{finalize:function(k,v){return Object.keys(v).reduce((a,b)=>v[a]>v[b]?a:b);},out:{"inline":1},query:{"power_control_faction":{"$exists":1}}})
	</pre>
	</div>		</div>

40166222 at 00:22, 23 March 2018

2018-03-23T00:22:01Z

← Older revision		Revision as of 00:22, 23 March 2018
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	<p class="strong">Using the result from the previous question, guess the power's allegiance by the faction that the majority of their systems follow.</p>		<p class="strong">Using the result from the previous question, guess the power's allegiance by the faction that the majority of their systems follow.</p>
	<p>To achieve this, you'll need to use the <code>finalize: function(k, v){}</code> in the third argument to find the key with the largest value.</p>		<p>To achieve this, you'll need to use the <code>finalize: function(k, v){}</code> in the third argument to find the key with the largest value.</p>
	<div class="hint" title="Example"><~~code~~>Zemina Torval: Empire</~~code~~></div>		<div class="hint" title="Example">
			<pre>
			{
			"_id" : "Zemina Torval",
			"value" : "Empire"
			}
			</pre></div>
	<pre class="def">		<pre class="def">
	db.systems.mapReduce(		db.systems.mapReduce(

40166222 at 00:19, 23 March 2018

2018-03-23T00:19:51Z

← Older revision		Revision as of 00:19, 23 March 2018
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	<pre>		<pre>
	{ '_id': 'Zemina Torval',		{ '_id': 'Zemina Torval',
	'value': { '~~alliance~~': 0.0,		'value': { 'Alliance': 0.0,
	'~~anarchy~~': 0.0,		'Anarchy': 0.0,
	'~~empire~~': 39.0,		'Empire': 39.0,
	'~~federation~~': 3.0,		'Federation': 3.0,
	'~~independent~~': 5.0}}]		'Independent': 5.0}}]
	</pre>		</pre>
	</div>		</div>

40166222: /* Questions */

2018-03-23T00:18:45Z

Questions

← Older revision		Revision as of 00:18, 23 March 2018
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	<p class="strong">What are the populations of the three main factions?</p>		<p class="strong">What are the populations of the three main factions?</p>
	<div class="hint" title="Three main factions">["Alliance","Federation","Empire"]</div>		<div class="hint" title="Three main factions">["Alliance","Federation","Empire"]</div>
	<div class="hint" title="NaN?">Some systems have ~~no populations~~, make sure to exclude them using <code>!isNaN()</code>.</div>		<div class="hint" title="NaN?">Some systems are not populated and will have '''null''' population fields, make sure to exclude them using <code>!isNaN()</code>.</div>
	<pre class="def">		<pre class="def">
	db.systems.mapReduce(		db.systems.mapReduce(
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	)		)
	</pre>		</pre>
	<pre class="ans">db.systems.mapReduce(function(){if (!isNaN(this.population) && this.allegiance!=null && this.allegiance!="Independent" && this.allegiance!="Anarchy"){emit(this.allegiance, this.population);}},function(k,v){return Array.sum(v);},{out:{inline:1}})</pre>		<pre class="ans">db.systems.mapReduce(function(){if(!isNaN(this.population)&&this.allegiance!=null&&this.allegiance!="Independent"&&this.allegiance!="Anarchy"){emit(this.allegiance,this.population);}},function(k,v){return Array.sum(v);},{out:{inline:1}})</pre>
	</div>		</div>

	==Harder Questions==		==Harder Questions==
	<div class="q" data-lang="mongo" data-switches='elite'>How much Hydrogen Fuel is owned by each faction? Limit your query to the first 5000 stations.		<div class="q" data-lang="mongo" data-switches='elite'>How much Hydrogen Fuel is owned by each faction? Limit your query to the first 5000 stations.

40166222: Rewording.

2018-03-23T00:14:43Z

Rewording.

← Older revision		Revision as of 00:14, 23 March 2018
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	</div>		</div>
	==Harder Questions==		==Harder Questions==
	<div class="q" data-lang="mongo" data-switches='elite'>How much Hydrogen Fuel is owned by ~~stations in systems.~~ Limit your query to the first 5000 stations.		<div class="q" data-lang="mongo" data-switches='elite'>How much Hydrogen Fuel is owned by each faction? Limit your query to the first 5000 stations.
	<div class="hint" title="hint">		<div class="hint" title="hint">
	The amount of stations <b>and</b> the amount of listings aren't fixed~~, you'll need to~~ <code>query</code> to ensure that they exist ~~and find a way of iterating through them in your <code>map</code> stage~~.		The amount of stations in a system <b>and</b> the amount of listings to a station aren't fixed. <code>query</code> can be used to ensure that they exist.
	</div>		</div>
	<pre class="def">		<pre class="def">
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	</div>		</div>
	<div class="q" data-lang="mongo" data-switches='elite'>A <code>power_control_faction</code> or <b>Power</b> is an individual or organisation who is in control of a system.<br/>		<div class="q" data-lang="mongo" data-switches='elite'>A <code>power_control_faction</code> or <b>Power</b> is an individual or organisation who is in control of a system.<br/>
	These powers have ~~allegiances~~, but the systems they control do not nescessarily have the same allegiance as they do.		These powers have allegiance to a faction, but the systems they control do not nescessarily have the same allegiance that they do.
	<div class="hint" title="Example"> At the time of writing <b>Zemina Torval</b> is allied with the <b>Empire</b> and controls <b>47</b> systems.<br/>		<div class="hint" title="Example"> At the time of writing <b>Zemina Torval</b> is allied with the <b>Empire</b> and controls <b>47</b> systems.<br/>
	<pre>		<pre>

40166222: Clarify Q6.

2018-03-23T00:11:34Z

Clarify Q6.

← Older revision		Revision as of 00:11, 23 March 2018
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	</div>		</div>
	<pre class="def">		<pre class="def">
	db.~~commodities~~.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1,1);
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	<p class="strong">Show the allegiance of each of the power's systems</p>		<p class="strong">Show the allegiance of each of the power's systems</p>
	<pre class="def">		<pre class="def">
	db.~~commodities~~.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1,1);
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	return Array.sum(v);		return Array.sum(v);
	},		},
	{out:{inline:1}}		{
			query: {"power_control_faction": {"$exists": 1}},
			out: {inline: 1}
			}
	)		)
	</pre>		</pre>
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	<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:		<div class="q" data-lang="mongo" data-switches='elite'>Our dataset doesn't contain the allegiance of a power:
	<p class="strong">Using the result from the previous question, guess the power's allegiance by the faction that the majority of their systems follow.</p>		<p class="strong">Using the result from the previous question, guess the power's allegiance by the faction that the majority of their systems follow.</p>
	<div class="hint" title="Example"><code>Zemina Torval: Empire~~(39.0)~~</code></div>		<p>To achieve this, you'll need to use the <code>finalize: function(k, v){}</code> in the third argument to find the key with the largest value.</p>
			<div class="hint" title="Example"><code>Zemina Torval: Empire</code></div>
	<pre class="def">		<pre class="def">
	db.~~commodities~~.mapReduce(		db.systems.mapReduce(
	function(){		function(){
	emit(1,1);		emit(1,1);
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	return Array.sum(v);		return Array.sum(v);
	},		},
	{out:{inline:1}}		{
			finally: function(k, v){
			return v;
			},
			query: {"power_control_faction": {"$exists": 1}},
			out: {inline: 1}
			}
	)		)
	</pre>		</pre>