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the input keys are arbitrary in this example
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in other examples they might not be
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the purpose of this test
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is to show how map reduce works
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this data set is for the word count example
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the first line is a key
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if you start with zero as the first line
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then even line numbers are keys in the map file
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odd line numbers are values in the map file
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in the word count example
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values are sequences of words separated by spaces
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you can try your own data set to play with this demo
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the data will be written as key value pairs in files of type red
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red is short for reduce