Difference between revisions of "MAPREDUCE basics"
From NoSQLZoo
| Line 13: | Line 13: | ||
pp = pprint.PrettyPrinter(indent=4) | pp = pprint.PrettyPrinter(indent=4) | ||
</pre> | </pre> | ||
| + | |||
| + | <div class=q data-lang="py3"> | ||
| + | <p class=strong>Show a list of countries found in North America</p> | ||
| + | <pre class=def> | ||
| + | from bson.code import Code | ||
| + | temp = db.world.map_reduce( | ||
| + | query={"continent":"Africa"}, | ||
| + | map=Code("function(){emit(this.continent, this.name)}"), | ||
| + | reduce=Code("function(key, values){return values.toString()}"), | ||
| + | out={"inline":1} | ||
| + | ) | ||
| + | |||
| + | pp.pprint( | ||
| + | temp["results"] | ||
| + | ) | ||
| + | </pre> | ||
| + | <div class=ans> | ||
| + | from bson.code import Code | ||
| + | temp = db.world.map_reduce(query={"continent":"North America"},map=Code("function(){emit(this.continent, this.name)}"), reduce=Code("function(key, values){return values.toString()}"),out={"inline":1},) | ||
| + | pp.pprint(temp["results"]) | ||
| + | </div> | ||
| + | </div> | ||
| + | |||
| + | <div class=q data-lang="py3"> | ||
| + | <p class=strong>Show the number of countries on each continent</p> | ||
| + | <pre class=def> | ||
| + | </pre> | ||
| + | <div class=ans> | ||
| + | from bson.code import Code | ||
| + | temp = db.world.map_reduce(map=Code("function(){emit(this.continent, this.name)}"), reduce=Code("function(key, values){return values.length}"),out={"inline":1}) | ||
| + | pp.pprint(temp["results"]) | ||
| + | </div> | ||
| + | </div> | ||
Revision as of 14:49, 29 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)
Show a list of countries found in North America
from bson.code import Code
temp = db.world.map_reduce(
query={"continent":"Africa"},
map=Code("function(){emit(this.continent, this.name)}"),
reduce=Code("function(key, values){return values.toString()}"),
out={"inline":1}
)
pp.pprint(
temp["results"]
)
from bson.code import Code temp = db.world.map_reduce(query={"continent":"North America"},map=Code("function(){emit(this.continent, this.name)}"), reduce=Code("function(key, values){return values.toString()}"),out={"inline":1},) pp.pprint(temp["results"])
Show the number of countries on each continent
from bson.code import Code temp = db.world.map_reduce(map=Code("function(){emit(this.continent, this.name)}"), reduce=Code("function(key, values){return values.length}"),out={"inline":1}) pp.pprint(temp["results"])