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Pig〔(【引用サイトリンク】title=Hadoop: Apache Pig )〕 is a high-level platform for creating MapReduce programs used with Hadoop. The language for this platform is called Pig Latin.〔 Pig Latin abstracts the programming from the Java MapReduce idiom into a notation which makes MapReduce programming high level, similar to that of SQL for RDBMS systems. Pig Latin can be extended using UDF (User Defined Functions) which the user can write in Java, Python, JavaScript, Ruby or Groovy〔(【引用サイトリンク】title=Pig user defined functions )〕 and then call directly from the language. Pig was originally〔(【引用サイトリンク】title=Yahoo Blog:Pig – The Road to an Efficient High-level language for Hadoop )〕 developed at Yahoo Research around 2006 for researchers to have an ad-hoc way of creating and executing map-reduce jobs on very large data sets. In 2007,〔(【引用サイトリンク】title=Pig into Incubation at the Apache Software Foundation )〕 it was moved into the Apache Software Foundation.〔(【引用サイトリンク】title=The Apache Software Foundation )〕 ==Example== Below is an example of a "Word Count" program in Pig Latin: input_lines = LOAD '/tmp/my-copy-of-all-pages-on-internet' AS (line:chararray); -- Extract words from each line and put them into a pig bag -- datatype, then flatten the bag to get one word on each row words = FOREACH input_lines GENERATE FLATTEN(TOKENIZE(line)) AS word; -- filter out any words that are just white spaces filtered_words = FILTER words BY word MATCHES '\\w+'; -- create a group for each word word_groups = GROUP filtered_words BY word; -- count the entries in each group word_count = FOREACH word_groups GENERATE COUNT(filtered_words) AS count, group AS word; -- order the records by count ordered_word_count = ORDER word_count BY count DESC; STORE ordered_word_count INTO '/tmp/number-of-words-on-internet'; The above program will generate parallel executable tasks which can be distributed across multiple machines in a Hadoop cluster to count the number of words in a dataset such as all the webpages on the internet. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pig (programming tool)」の詳細全文を読む スポンサード リンク
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