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  • pig—WordCount analysis

     grunt> cat /opt/dataset/input.txt
    	keyword1 keyword2
    	keyword2 keyword4
    	keyword3 keyword1
    	keyword4 keyword4
     A = LOAD '/opt/dataset/input.txt' using PigStorage('
    ')  as (line:chararray);
     B = foreach A generate TOKENIZE((chararray)$0);
     C = foreach B generate flatten($0) as word;
     D = group C by word;
     E = foreach D generate COUNT(C), group;
     dump B;
    ({(keyword1),(keyword2)})
    ({(keyword2),(keyword4)})
    ({(keyword3),(keyword1)})
    ({(keyword4),(keyword4)})
     dump C;
    (keyword1)
    (keyword2)
    (keyword2)
    (keyword4)
    (keyword3)
    (keyword1)
    (keyword4)
    (keyword4)
     dump D;
    (keyword1,{(keyword1),(keyword1)})
    (keyword2,{(keyword2),(keyword2)})
    (keyword3,{(keyword3)})
    (keyword4,{(keyword4),(keyword4),(keyword4)})
     dump E;
    (2,keyword1)
    (2,keyword2)
    (1,keyword3)
    (3,keyword4)
     store E into './wordcount';
    TOKENIZE
    Splits a string and outputs a bag of words.
    
    Syntax
    TOKENIZE(expression)       
    
    Terms
    expression
    
    An expression with data type chararray.
    
    Usage
    Use the TOKENIZE function to split a string of words (all words in a single tuple) into a bag of words (each word in a single tuple). The following characters are considered to be word separators: space, double quote("), coma(,) parenthesis(()), star(*).
    
    Example
    In this example the strings in each row are split.
    
    A  = LOAD 'data' AS (f1:chararray);
    
    DUMP A;
    (Here is the first string.)
    (Here is the second string.)
    (Here is the third string.)
    
    X = FOREACH A GENERATE TOKENIZE(f1);
    
    DUMP X;
    ({(Here),(is),(the),(first),(string.)})
    ({(Here),(is),(the),(second),(string.)})
    ({(Here),(is),(the),(third),(string.)})


    
    
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  • 原文地址:https://www.cnblogs.com/bhlsheji/p/3781567.html
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