Standard deviation using mrjob in Python is showing the error "file has no attributes to run"

Question

from mrjob.job import MRJob
import statistics
import sys

class MRFindStdev():

    def mapper(self, _, line):
        for number in line.split(','):
            yield number, float(number)

    def reducer(self, _, line):
        numbers = list(self.mapper(line))
        #total_numbers = len(numbers)
        #mean = sum(numbers)/total_numbers
        #print(numbers)
        yield statistics.stdev(numbers)


if __name__ == '__main__':
  MRFindStdev.run()

Put MRJob in () when you define the class as per my previous comment. That tells Python to use the class MRJob as a template when MRFindStdev is created. — zan, Mar 04 '19 at 08:29

Shubham Jadhav · Answer 1 · 2019-03-24T00:37:31.533

1

try the following

from statistics import stdev
import statistics

class deviation(MRJob):
    def mapper(self, __, line):
        for num in line.split(','):
            yield None, int(num)


    def reducer(self, __, numbr):
        yield "deviation",statistics.stdev(numbr)

if __name__ == '__main__':
    deviation.run()

edited Mar 24 '19 at 00:37

answered Mar 24 '19 at 00:31

Shubham Jadhav

11
2

score 0 · Answer 2 · answered Mar 04 '19 at 20:37

0

I'll turn my comment into an answer, so it can be accepted.

Subclass MRJob when creating MRFindStdev:

class MRFindStdev(MRJob):
    def mapper(self, _, line):
        # code...

answered Mar 04 '19 at 20:37

zan

441
2
8

Standard deviation using mrjob in Python is showing the error "file has no attributes to run"

2 Answers2