39 lines
1.0 KiB
Python
39 lines
1.0 KiB
Python
#!/usr/bin/env python
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from operator import itemgetter
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import sys
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current_word = None
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current_count = 0
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word = None
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# input comes from STDIN
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for line in sys.stdin:
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# remove leading and trailing whitespace
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line = line.strip()
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# parse the input we got from mapper.py
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word, count = line.split('\t', 1)
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# convert count (currently a string) to int
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try:
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count = int(count)
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except ValueError:
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# count was not a number, so silently
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# ignore/discard this line
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continue
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# this IF-switch only works because Hadoop sorts map output
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# by key (here: word) before it is passed to the reducer
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if current_word == word:
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current_count += count
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else:
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if current_word:
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# write result to STDOUT
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print('%s\t%s' % (current_word, current_count))
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current_count = count
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current_word = word
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# do not forget to output the last word if needed!
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if current_word == word:
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print('%s\t%s' % (current_word, current_count))
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