Refers to reducers in the mapreduce framework. Mappers split up a large problem and solve parts of it in parallel. Reducers collect and summarize the output of a map method.
Reference: https://en.wikipedia.org/wiki/MapReduce
Questions tagged [reducers]
791 questions
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1 answer
java.lang.Exception: java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.hadoop.io.IntWritable
public class PrimeMapper extends Mapper
{
public void map(LongWritable k,IntWritable val,Context c) throws IOException, InterruptedException
{
int…
AcCesS DoOmeR
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votes
1 answer
Hbase Error: java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.hadoop.hbase.client.Mutation
I am getting following error while transferring values from one Hbase table to other Hbase table. The code is working fine while transferring from Hbase table to file output.
Error: java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be…
stonecrusher
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votes
2 answers
Categorizing words according to their length on reducer
I am new on MapReduce applications. I'm simply trying to find words' length on my data set and categorize them as tiny, little, med, huge according to their length and in the end, I want to see the total number how many words are tiny, little, med…
Sarlken Konig
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votes
3 answers
Array.length in map reduce throwing Null pointer exception
This is the code i am using in mapreduce and getting a null pointer exception..I am passing a variable via configuration, getting that as string and parsing and storing in an int array and processing that--
int[] results;
public void…
Muthu Palaniappan
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votes
1 answer
hadoop output file unrecognizable characters
I don't know how it happened, but suddenly my output file from my hadoop reducer contains a bunch of characters which I never put it in. The first few lines are…
King Saber
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votes
1 answer
Can my reducer's output key type be different than input?
Actually my key to reducer is custom key (word1, word2) and I want to write output, in format like "word1\tword2" . And I'm not able to do that.
Any help appreciated.
Thanks.
EDIT: there was already \t between pair... I didn't notice it!
code muncher
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votes
0 answers
Calling queries from graphCMS in Reducers(Redux), is it possible?
So we're newly introduced to redux in our course and i'm using graphCMS so we can create products and fetch that data by queries. But, when we got introduced to redux and access the data more easily instead of passing props all over, it doesn't work…
Linus
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votes
3 answers
array of array sum and breaks when if-condition meet
I have a js array like this.
const test_arr = [ [ 20, 7, 23, 19, 10, 15, 25 ],
[ 20, 7, 23, 19, 10, 15, 8 ],
[ 20, 7, 23, 19, 10, 15, 13 ],
[ 20, 7, 23, 19, 10, 25, 8 ],
[ 20, 7, 23, 19, 10, 25, 13 ],
[ 20, 7, 23, 19, 10, 8, 13 ],
[ 20,…
horoyoi o
- 398
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votes
1 answer
Update to state does not get displayed in component in Redux
I update transcriptDisplay in reducer(I have a method on button click to update the state). I can see it getting updated in state tree.
case actions.TRANSCRIPT_GET:
return Object.assign({}, state, {
transcriptDisplay: action.payload,
…
funkadelic
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votes
1 answer
How to pass Badge Value with Redux to BottomTabBar on React Native
How to change Badge Value on BottomTabBar using Redux ?
Value Badge on BottomTabBar with Redux (99+) there i want to change it with value from redux
Connect
Rakha Hidayat
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votes
2 answers
How to delete state in every Reducer with single action
I have 10 reducer and I want to delete state values in every reducer with
a single click, how can I achieve this?
mustafa bagwala
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