Difference between revisions of "AGGREGATE world"
From NoSQLZoo
| Line 20: | Line 20: | ||
Give the <code>name</code> and the <b>per capita GDP</b> for those countries with a <code>population</code> of at least 200 million. | Give the <code>name</code> and the <b>per capita GDP</b> for those countries with a <code>population</code> of at least 200 million. | ||
<div class="hint" title="How to calculate per capita GDP"> | <div class="hint" title="How to calculate per capita GDP"> | ||
| − | per capita GDP is the GDP divided by the population | + | per capita GDP is the GDP divided by the population. |
</div> | </div> | ||
<pre class=def> | <pre class=def> | ||
| Line 32: | Line 32: | ||
"name":1, | "name":1, | ||
"per capita GDP": {"$divide": ["$gdp",1000000]} | "per capita GDP": {"$divide": ["$gdp",1000000]} | ||
| + | }} | ||
| + | ]) | ||
| + | )) | ||
| + | </pre> | ||
| + | <div class=ans>pp.pprint(list(db.world.aggregate([{"$match":{"population":{"$gte":200000000}}},{"$project":{"_id":0,"name":1,"per capita GDP": {"$divide": ["$gdp","$population"]}}}]))) | ||
| + | </div> | ||
| + | </div> | ||
| + | |||
| + | <div class=q data-lang="py3"> | ||
| + | Give the <code>name</code> and the <b>population density</b> of all countries. | ||
| + | <div class="hint" title="How to calculate population density"> | ||
| + | population density is the population divided by the area | ||
| + | </div> | ||
| + | <pre class=def> | ||
| + | pp.pprint(list( | ||
| + | db.world.aggregate([ | ||
| + | {"$project":{ | ||
| + | "_id":0, | ||
| + | "name":1, | ||
| + | "per capita GDP": {"$divide": [10000,"$area"]} | ||
}} | }} | ||
]) | ]) | ||
Revision as of 12:14, 17 July 2015
#ENCODING
import io
import sys
sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-16')
#MONGO
from pymongo import MongoClient
client = MongoClient()
client.progzoo.authenticate('scott','tiger')
db = client['progzoo']
#PRETTY
import pprint
pp = pprint.PrettyPrinter(indent=4)
Country Profile
For these questions you should use aggregate([]) on the collection world
Give the name and the per capita GDP for those countries with a population of at least 200 million.
per capita GDP is the GDP divided by the population.
pp.pprint(list(
db.world.aggregate([
{"$match":{
"population":{"$gte":250000000}
}},
{"$project":{
"_id":0,
"name":1,
"per capita GDP": {"$divide": ["$gdp",1000000]}
}}
])
))
pp.pprint(list(db.world.aggregate([{"$match":{"population":{"$gte":200000000}}},{"$project":{"_id":0,"name":1,"per capita GDP": {"$divide": ["$gdp","$population"]}}}])))
Give the name and the population density of all countries.
population density is the population divided by the area
pp.pprint(list(
db.world.aggregate([
{"$project":{
"_id":0,
"name":1,
"per capita GDP": {"$divide": [10000,"$area"]}
}}
])
))
pp.pprint(list(db.world.aggregate([{"$match":{"population":{"$gte":200000000}}},{"$project":{"_id":0,"name":1,"per capita GDP": {"$divide": ["$gdp","$population"]}}}])))