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]
819 questions
0
votes
1 answer
What vaue to be set for mappers and reducers while executing jobs in hadoop and how to decide it?
I am running Hive jobs on hadoop cluster. I just came to know to know that the performance will get improve/change if you just concentrate on different behavior mapper and reducer. But I haven't played with it until. Until no I just played with Hive…
Bhavesh Shah
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0
votes
4 answers
How to increase the mappers and reducers in hadoop according to number of instances used to increase the performance?
If I increase the number of mappers and decrease the number of reducers, then is there any difference in the performance (increase/decrease) of any job while execution?
Also I want to ask that How to set the number of mappers and reducers? I have…
Bhavesh Shah
- 3,299
- 11
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- 73
-1
votes
1 answer
I'm getting a list of lists in my reducer output rather than a paired value and I am unsure of what to change in my code
The code below is giving me nearly the output i want but not quite.
def reducer(self, year, words):
x = Counter(words)
most_common = x.most_common(3)
sorted(x, key=x.get, reverse=True)
yield (year,…
CKZ
- 37
- 5
-1
votes
1 answer
how to get array from object with index as one of the object property
I have an object
const items = {
"123": {
"key": 123,
"name": "one name",
},
"456": {
"key": 456,
"name": "two name",
},
"789": {
"key": 789,
"name": "three name",
},
};
Need to filter this from…
codingHack
- 21
- 3
-1
votes
1 answer
Fetch data from back end to front end after getting it in router from database
I am building a mern expo app login and signin page. When clicking the signin button it should login but I couldn't get the data from the backend though i already made the find query inside the router express. I believe my code will help you…
Sang Tonsing
- 137
- 3
- 14
-1
votes
2 answers
My list isn't updating when i use the method put and post, only when i press F5
I'm trying to do a form using react and redux but when i add or edit something, only when i press F5 the list updates in my table.
what am i doing wrong?
Before i implemented redux, my table was updating.
My reducer:
const initialState = {
member:…
user14801080
- 1
- 4
-1
votes
2 answers
Reducer that can be re-used in different branches of the same Redux state?
I wonder if there's any established pattern of having a reducer that can be re-used in different branches of the same global Redux state?
Typical example would be pagination. Every table grid has same params, like: data, pageNumber, pageSize,…
jayarjo
- 16,124
- 24
- 94
- 138
-1
votes
2 answers
Filtering data in reducer
I have the problem with sorting via reducer in ngrx.
The table was filled by the selector - ok great.
Now, I would like to implement a filter solution for table data - contains, start with, etc. And in my opinion, the best solution will be using…
profiler
- 567
- 2
- 15
- 41
-1
votes
2 answers
React Redux: How to properly return iteratable array in reducer?
I'm working in React Redux, and I am trying to return a value from a simple array in my reducer. Here are my short files:
App.js
let arr = [{"name": "Matthew"}];
function App() {
const dispatch = useDispatch();
dispatch(action1(arr));
…
user545642
- 91
- 1
- 14
-1
votes
1 answer
Is reducer and global variable are the same?
Can I get the reducer state in Browser console like accessing declared javascript variables.?
Sriramamoorthy S
- 1
- 1
-1
votes
2 answers
MapReduce Reducer of 2 Keys - Python
This should be pretty simple and I have put a few hours into this.
Example Data (name, binary, count):
Adam 0 1
Adam 1 1
Adam 0 1
Mike 1 1
Mike 0 1
Mike 1 1
Desired Example Output (name, binary, count):
Adam 0 2
Adam 1 1
Mike 0 1
Mike 1 2 …
CP3
- 1
- 1
-1
votes
2 answers
count objects from an array with that object and count of that object
I have this code snippet. and want to count duplicate applicationType along with applicationType and count both.
{
applicationType:"Supplemental Marketing Application",
createdBy:"System"
},
{
applicationType:"Supplemental Marketing…
JSCoder
- 5
- 4
-1
votes
1 answer
What is the correct way to perform multiple operations on a text file , but executing it as a SINGLE HADOOP JOB
I want to perform few operations on a single text file.
For eg:
Task 1: Count all the words
Task 2: Count words ending with specific characters
Task 3: Count words occuring multiple times.
What is the best way of achieving this?
Do I need to write…
TjS
- 277
- 2
- 5
- 16
-1
votes
2 answers
What separates a transformer from a reducer ? - Clojure
From what I gather a transformer is the use of functions that change , alter , a collection of elements . Like if I did added 1 to each element in a collection of
[1 2 3 4 5]
and it became
[2 3 4 5 6]
but writing the code for this looks like…
Alex
- 31
- 3
-1
votes
2 answers
update the value of an object for a specific index during an state change in a reducer
I have an array of objects which has the following structure:
const obj = Object.assign({}, state.stuff.data);
where the value of obj is :
[
abc-123:{x: "1", y: "2", value: "", latency: ""},
efg-345:{x: "1", y: "2", value: "", latency:…
pj013
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