FIND from WORLD - Revision history

Cs66 at 10:34, 13 November 2015

2015-11-13T10:34:29Z

← Older revision		Revision as of 10:34, 13 November 2015
Line 61:		Line 61:
	db.world.aggregate([		db.world.aggregate([
	{"$match":{"population":{"$gt":200000000}}},		{"$match":{"population":{"$gt":200000000}}},
	{"$project":{"name":1, "~~gdp/population~~":{"$divide":["$gdp","$population"]}, "_id":0}}		{"$project":{"name":1, "per capita GDP":{"$divide":["$gdp","$population"]}, "_id":0}}
	])		])
	))		))
	</pre>		</pre>
	~~<div class=ans>~~
	~~pp.pprint(list(db.world.aggregate([{"$match":{"population":{"$gt":200000000}}},{"$project":{"name":1, "gdp/population":{"$divide":["$gdp","$population"]}, "_id":0}}])))~~
	~~</div>~~
	</div>		</div>

40082593 at 13:54, 29 July 2015

2015-07-29T13:54:05Z

@@ Line 214: / Line 214: @@
          {"$project":{
              "name":1,
-             "continent":{"$cond":[{"$eq":["$continent","Oceania"]},"Austalasia","$continent"]},
+             "continent":{"$cond":[{"$eq":["$continent","Oceania"]},"Australasia","$continent"]},
              "_id":0
          }}
@@ Line 221: / Line 221: @@
 </pre>
 <div class=ans>
-pp.pprint(list(db.world.aggregate([{"$match":{"name":{"$regex":"^N"}}},{"$project":{"name":1,"continent":{"$cond":[{"$eq":["$continent","Oceania"]},"Austalasia","$continent"]},"_id":0}}])))
+pp.pprint(list(db.world.aggregate([{"$match":{"name":{"$regex":"^N"}}},{"$project":{"_id":0,"name":1,"continent":{"$cond":[{"$eq":["$continent","Oceania"]},"Australasia","$continent"]}}}])))
 </div>
 </div>
 <div class=q data-lang="py3">
-Show the <b>name</b> and the <b>continent</b> for countries beginning with N - but replace the continent <b>Oceania</b> with <b>Australasia</b>.
+Show the <b>name</b> and the <b>continent</b> but:<br/><br/>
 <pre class=def>
 pp.pprint(list(
      db.world.aggregate([
          {"$match":{
-             "name":{"$regex":"^N"}
+             "name":{"$regex":"^A|^B"}
          }},
          {"$project":{
              "_id":0,
-             "name":1
+             "name":1,
          }}
      ])
 ))
 </pre>
 <div class=ans>
 pp.pprint(list(
@@ Line 287: / Line 292: @@
 <br/><br/>
 <b>Show the name, the original continent and the new continent of all countries.</b>
-<pre class=def></pre>
+<pre class=def>
 <div class=ans>
 pp.pprint(list(

40082593 at 13:40, 29 July 2015

2015-07-29T13:40:14Z

@@ Line 222: / Line 222: @@
 <div class=ans>
 pp.pprint(list(db.world.aggregate([{"$match":{"name":{"$regex":"^N"}}},{"$project":{"name":1,"continent":{"$cond":[{"$eq":["$continent","Oceania"]},"Austalasia","$continent"]},"_id":0}}])))
 </div>
 </div>

40082593 at 13:37, 29 July 2015

2015-07-29T13:37:27Z

@@ Line 200: / Line 200: @@
 return {'per-capita GDP':Math.round((v['gdp']/v['pop'])/1000)*1000};}"""),out={"inline":1})
 pp.pprint(temp['results']);
 </div>
 </div>

40082593 at 12:44, 29 July 2015

2015-07-29T12:44:43Z

← Older revision		Revision as of 12:44, 29 July 2015
Line 170:		Line 170:
	out={"inline":1}		out={"inline":1}
	)		)

	pp.pprint(temp['results']);		pp.pprint(temp['results']);
	</pre>		</pre>
	<div class=ans>		<div class=ans>
	from bson.code import Code		from bson.code import Code
	temp = db.world.map_reduce(query={"continent":"South America"},map=Code("function(){emit(this.name,{'gdp':this.gdp,'pop':this.population});}"), reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'pop in millions':~~math~~.~~Round~~(v['pop']/1000000)/1000000,'gdp in billions':~~math~~.~~Round~~(v['gdp']/1000000000)/1000000000};}"""),out={"inline":1})		temp = db.world.map_reduce(query={"continent":"South America"},map=Code("function(){emit(this.name, {'gdp':this.gdp,'pop':this.population});}"),reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'pop in millions':Math.round(v['pop']1000000)/1000000,'gdp in billions':Math.round(v['gdp']1000000000)/1000000000};}"""),out={"inline":1})

	pp.pprint(temp['results']);		pp.pprint(temp['results']);
	</div>		</div>
Line 199:		Line 197:
	<div class=ans>		<div class=ans>
	from bson.code import Code		from bson.code import Code
	temp = db.world.map_reduce(map=Code("function(){if(this.gdp > 1000000000000)emit(this.name,{'gdp':this.gdp,'pop':this.population});}"),reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'per-capita GDP':Math.round((v['gdp']/v['pop'])/1000)*1000};}"""),out={"inline":1})pp.pprint(temp['results']);		temp = db.world.map_reduce(map=Code("function(){if(this.gdp > 1000000000000)emit(this.name,{'gdp':this.gdp,'pop':this.population});}"),reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){
			return {'per-capita GDP':Math.round((v['gdp']/v['pop'])/1000)*1000};}"""),out={"inline":1})
			pp.pprint(temp['results']);
	</div>		</div>
	</div>		</div>

40082593 at 12:30, 29 July 2015

2015-07-29T12:30:54Z

← Older revision		Revision as of 12:30, 29 July 2015
Line 163:		Line 163:
	finalize=Code("""function(k, v){		finalize=Code("""function(k, v){
	return {		return {
	'pop in millions':~~parseFloat(~~(v['pop']/1000000~~).toFixed(2))~~,		'pop in millions':Math.round(v['pop']*1000000)/1000000,
	'gdp in billions':~~parseFloat(~~(v['gdp']/1000000000~~).toFixed(2))~~		'gdp in billions':Math.round(v['gdp']*1000000000)/1000000000
	};		};
	}		}
Line 175:		Line 175:
	<div class=ans>		<div class=ans>
	from bson.code import Code		from bson.code import Code
	temp = db.world.map_reduce(query={"continent":"South America"},map=Code("function(){emit(this.name,{'gdp':this.gdp,'pop':this.population});}"), reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'pop in millions':~~parseFloat(~~(v['pop']/1000000)~~.toFixed(2))~~,'gdp in billions':~~parseFloat(~~(v['gdp']/1000000000)~~.toFixed(2))~~};}"""),out={"inline":1})		temp = db.world.map_reduce(query={"continent":"South America"},map=Code("function(){emit(this.name,{'gdp':this.gdp,'pop':this.population});}"), reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'pop in millions':math.Round(v['pop']/1000000)/1000000,'gdp in billions':math.Round(v['gdp']/1000000000)/1000000000};}"""),out={"inline":1})

	pp.pprint(temp['results']);		pp.pprint(temp['results']);
Line 187:		Line 187:
	from bson.code import Code		from bson.code import Code
	temp = db.world.map_reduce(		temp = db.world.map_reduce(
	~~query={"continent":"South America"},~~		map=Code("function(){if(this.gdp > 1000000000000)emit(this.name,{'gdp':this.gdp,'pop':this.population});}"),
	map=Code("function(){emit(this.name,{'gdp':this.gdp,'pop':this.population});}"),
	reduce=Code("""function(key, values){ return values} """),		reduce=Code("""function(key, values){ return values} """),
	finalize=Code("""function(k, v){		finalize=Code("""function(k, v){
	return {		return {'per-capita GDP':Math.round((v['gdp']/v['pop'])/1000)*1000};
	'~~pop in millions~~':~~parseFloat~~((v['~~pop~~']/~~1000000).toFixed(2)),~~
	~~'gdp in billions':parseFloat((~~v['~~gdp~~']/~~1000000000).toFixed(2)~~)
	};
	}		}
	"""),		"""),
	out={"inline":1}		out={"inline":1}
	)		)

	pp.pprint(temp['results']);		pp.pprint(temp['results']);
	</pre>		</pre>
	<div class=ans>		<div class=ans>
	from bson.code import Code		from bson.code import Code
	temp = db.world.map_reduce(~~query={"continent":"South America"},~~map=Code("function(){emit(this.name,{'gdp':this.gdp,'pop':this.population});}"), reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'~~pop in millions~~':~~parseFloat~~((v['~~pop~~']/~~1000000).toFixed(2)),'gdp in billions':parseFloat((~~v['~~gdp~~']/~~1000000000).toFixed(2)~~)};}"""),out={"inline":1})		temp = db.world.map_reduce(map=Code("function(){if(this.gdp > 1000000000000)emit(this.name,{'gdp':this.gdp,'pop':this.population});}"),reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'per-capita GDP':Math.round((v['gdp']/v['pop'])/1000)*1000};}"""),out={"inline":1})pp.pprint(temp['results']);

	pp.pprint(temp['results']);
	</div>		</div>
	</div>		</div>

40082593 at 12:19, 29 July 2015

2015-07-29T12:19:55Z

@@ Line 156: / Line 156: @@
 <p class=strong>For South America show population in millions and GDP in billions to 2 decimal places.</p>
 <pre class=def>
 </pre>
 <div class=ans>
-pp.pprint(list(db.world.aggregate([
+from bson.code import Code
-  {"$match":{"continent":{"$eq":"South America"}}},
+temp = db.world.map_reduce(query={"continent":"South America"},map=Code("function(){emit(this.name,{'gdp':this.gdp,'pop':this.population});}"), reduce=Code("""function(key, values){ return values} """),finalize=Code("""function(k, v){return {'pop in millions':parseFloat((v['pop']/1000000).toFixed(2)),'gdp in billions':parseFloat((v['gdp']/1000000000).toFixed(2))};}"""),out={"inline":1})
-  {"$project":{"name":1,
-      "pop in millions":{"$divide":[{"$subtract":[{"$add":[{"$multiply":[{"$divide":['$population',1000000]},100]},0.5]},{"$mod":[{"$add":[{"$multiply":[{"$divide":['$population',1000000]},100]},0.5]},1]}]},100]},
+pp.pprint(temp['results']);
-      "gdp in billions":{"$divide":[{"$subtract":[{"$add":[{"$multiply":[{"$divide":['$gdp',1000000000]},100]},0.5]},{"$mod":[{"$add":[{"$multiply":[{"$divide":['$gdp',1000000000]},100]},0.5]},1]}]},100]},
+</div>
-      "_id":0}}
+</div>
-  ])
-))
+<div class=q data-lang="py3">
 </div>
 </div>

40082593 at 11:31, 29 July 2015

2015-07-29T11:31:42Z

@@ Line 43: / Line 43: @@
 pp.pprint(list(
      db.world.find(
-       {"population":{"$gt":250000000}},
+       {"population":{"$gt":200000000}},
        {"name":1, "_id":0}
+     )
@@ Line 58: / Line 58: @@
 <div class="hint" title="How to calculate per capita GDP">per capita GDP is the GDP divided by the population GDP/population</div>
 <pre class=def>
 </pre>
 <div class=ans>
@@ Line 67: / Line 73: @@
 <p class=strong>Show the name and population in millions for the countries of the continent 'South America'. Divide the population by 1000000 to get population in millions.</p>
 <pre class=def>
 </pre>
 <div class=ans>
@@ Line 76: / Line 88: @@
 <p class=strong>Show the name and population for France, Germany, Italy</p>
 <pre class=def>
 </pre>
 <div class=ans>
@@ Line 85: / Line 103: @@
 <p class=strong>Show the countries which have a name that includes the word 'United'</p>
 <pre class=def>
 </pre>
 <div class=ans>
@@ Line 93: / Line 117: @@
 <div class=q data-lang="py3">
 Two ways to be big: A country is big if it has an area of more than 3 million sq km or it has a population of more than 250 million.
-<p class=strong>Show the countries that are big by area or big by population. Show name, population and area</p>
+<div class=q data-lang="py3">
 <pre class=def>
 </pre>
 <div class=ans>
-pp.pprint(list(db.world.find({"$or":[{"area":{"$gt":3000000}},{"population":{"$gt":250000000}}]},{"name":1,"population":1,"area":1,"_id":0})))
+pp.pprint(list(db.world.aggregate([
 </div>
 </div>

40082593 at 16:16, 28 July 2015

2015-07-28T16:16:50Z

@@ Line 34: / Line 34: @@
 <div class=ans>
 pp.pprint(list(db.world.find({},{"name":1,"continent":1,"population":1,"_id":0})))
 </div>
 </div>

40082593 at 15:06, 28 July 2015

2015-07-28T15:06:08Z

← Older revision		Revision as of 15:06, 28 July 2015
Line 20:		Line 20:

	<div class=q data-lang="py3">		<div class=q data-lang="py3">
	~~Use <code>find()</code> to return~~ the ~~21st document in world~~		Observe the result of running a simple mongoDB command.
	<p class=strong>~~Show the 21st document in~~ world</p>		<p class=strong>FIND name, continent, population FROM world</p>
	<pre class=def>		<pre class=def>
	pp.pprint(		pp.pprint(list(
	db.world.find()		db.world.find({},{
	)		"name":1,
			"continent":1,
			"population":1,
			"_id":0
			})
			))
	</pre>		</pre>
	<div class=ans>		<div class=ans>
	pp.pprint(db.world.find()~~[20]~~)		pp.pprint(list(db.world.find({},{"name":1,"continent":1,"population":1,"_id":0})))
	</div>		</div>
	</div>		</div>