finding the minimum using map reduce
0
Im trying to find the minimum of data set and was given this example to help. The code gives me the maximum. I cant find what to change to make it find the min.
from mrjob.job import MRJob
from mrjob.step import MRStep
class HighestRevenue(MRJob):
def mapper_get_city(self, key, line):
# create a key-value pair with key: city and value: amount
line_cols = line.split(',')
yield line_cols[0], float(line_cols[2])
def combiner_process_city(self, city, amount):
# consolidates all key-value pairs of mapper function (performed at mapper nodes)
yield city, sum(amount)
def reducer_city_amount(self, city, amount):
# final consolidation of key-value pairs at reducer nodes
yield None, (city, sum(amount))
def secondReducer(self, city, amount):
self.aList =
for a in amount:
self.aList.append(a)
self.aList.sort(key=lambda x: x[1], reverse=True)
for m in range(0,1):
yield self.aList[0]
def steps(self):
return [
MRStep(mapper = self.mapper_get_city,
combiner = self.combiner_process_city,
reducer = self.reducer_city_amount),
MRStep(reducer = self.secondReducer)
]
python mapreduce
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
asked Nov 24 '18 at 17:54
georgegeorge
31
add a comment |
0
Im trying to find the minimum of data set and was given this example to help. The code gives me the maximum. I cant find what to change to make it find the min.
from mrjob.job import MRJob
from mrjob.step import MRStep
class HighestRevenue(MRJob):
def mapper_get_city(self, key, line):
# create a key-value pair with key: city and value: amount
line_cols = line.split(',')
yield line_cols[0], float(line_cols[2])
def combiner_process_city(self, city, amount):
# consolidates all key-value pairs of mapper function (performed at mapper nodes)
yield city, sum(amount)
def reducer_city_amount(self, city, amount):
# final consolidation of key-value pairs at reducer nodes
yield None, (city, sum(amount))
def secondReducer(self, city, amount):
self.aList =
for a in amount:
self.aList.append(a)
self.aList.sort(key=lambda x: x[1], reverse=True)
for m in range(0,1):
yield self.aList[0]
def steps(self):
return [
MRStep(mapper = self.mapper_get_city,
combiner = self.combiner_process_city,
reducer = self.reducer_city_amount),
MRStep(reducer = self.secondReducer)
]
python mapreduce
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
asked Nov 24 '18 at 17:54
georgegeorge
31
There is a good answer already. Just wanted to point out that in the future you might want to format your code in a nice way. And also try to post the minimal code snippet that is a working example, but can be understood very fast. These will increase the willingness of users to answer your question.
– zsomko
Nov 24 '18 at 18:15
add a comment |
0
0
0
Im trying to find the minimum of data set and was given this example to help. The code gives me the maximum. I cant find what to change to make it find the min.
from mrjob.job import MRJob
from mrjob.step import MRStep
class HighestRevenue(MRJob):
def mapper_get_city(self, key, line):
# create a key-value pair with key: city and value: amount
line_cols = line.split(',')
yield line_cols[0], float(line_cols[2])
def combiner_process_city(self, city, amount):
# consolidates all key-value pairs of mapper function (performed at mapper nodes)
yield city, sum(amount)
def reducer_city_amount(self, city, amount):
# final consolidation of key-value pairs at reducer nodes
yield None, (city, sum(amount))
def secondReducer(self, city, amount):
self.aList =
for a in amount:
self.aList.append(a)
self.aList.sort(key=lambda x: x[1], reverse=True)
for m in range(0,1):
yield self.aList[0]
def steps(self):
return [
MRStep(mapper = self.mapper_get_city,
combiner = self.combiner_process_city,
reducer = self.reducer_city_amount),
MRStep(reducer = self.secondReducer)
]
python mapreduce
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
asked Nov 24 '18 at 17:54
georgegeorge
31
Im trying to find the minimum of data set and was given this example to help. The code gives me the maximum. I cant find what to change to make it find the min.
from mrjob.job import MRJob
from mrjob.step import MRStep
class HighestRevenue(MRJob):
def mapper_get_city(self, key, line):
# create a key-value pair with key: city and value: amount
line_cols = line.split(',')
yield line_cols[0], float(line_cols[2])
def combiner_process_city(self, city, amount):
# consolidates all key-value pairs of mapper function (performed at mapper nodes)
yield city, sum(amount)
def reducer_city_amount(self, city, amount):
# final consolidation of key-value pairs at reducer nodes
yield None, (city, sum(amount))
def secondReducer(self, city, amount):
self.aList =
for a in amount:
self.aList.append(a)
self.aList.sort(key=lambda x: x[1], reverse=True)
for m in range(0,1):
yield self.aList[0]
def steps(self):
return [
MRStep(mapper = self.mapper_get_city,
combiner = self.combiner_process_city,
reducer = self.reducer_city_amount),
MRStep(reducer = self.secondReducer)
]
python mapreduce
python mapreduce
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
asked Nov 24 '18 at 17:54
georgegeorge
31
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
asked Nov 24 '18 at 17:54
georgegeorge
31
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
edited Nov 24 '18 at 21:58
Sven Harris
1,7571211
1,7571211
asked Nov 24 '18 at 17:54
georgegeorge
31
asked Nov 24 '18 at 17:54
georgegeorge
31
asked Nov 24 '18 at 17:54
georgegeorge
31
31
There is a good answer already. Just wanted to point out that in the future you might want to format your code in a nice way. And also try to post the minimal code snippet that is a working example, but can be understood very fast. These will increase the willingness of users to answer your question.
– zsomko
Nov 24 '18 at 18:15
add a comment |
There is a good answer already. Just wanted to point out that in the future you might want to format your code in a nice way. And also try to post the minimal code snippet that is a working example, but can be understood very fast. These will increase the willingness of users to answer your question.
– zsomko
Nov 24 '18 at 18:15
There is a good answer already. Just wanted to point out that in the future you might want to format your code in a nice way. And also try to post the minimal code snippet that is a working example, but can be understood very fast. These will increase the willingness of users to answer your question.
– zsomko
Nov 24 '18 at 18:15
There is a good answer already. Just wanted to point out that in the future you might want to format your code in a nice way. And also try to post the minimal code snippet that is a working example, but can be understood very fast. These will increase the willingness of users to answer your question.
– zsomko
Nov 24 '18 at 18:15
add a comment |
1 Answer
1
active
oldest
votes
1
remove reverse=True from sort procedure inside of secondReducer
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
1
remove reverse=True from sort procedure inside of secondReducer
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
add a comment |
1
remove reverse=True from sort procedure inside of secondReducer
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
add a comment |
1
1
1
remove reverse=True from sort procedure inside of secondReducer
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
remove reverse=True from sort procedure inside of secondReducer
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
answered Nov 24 '18 at 18:08
mangustamangusta
1,63921326
1,63921326
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
add a comment |
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
ty that solve the problem I was having. I assume that reverse statement just took the result as opposite.
– george
Nov 25 '18 at 7:18
add a comment |
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There is a good answer already. Just wanted to point out that in the future you might want to format your code in a nice way. And also try to post the minimal code snippet that is a working example, but can be understood very fast. These will increase the willingness of users to answer your question.
– zsomko
Nov 24 '18 at 18:15