STRSPLIT and REGEX_EXTRACT_ALL in PigLatin

问题

I have a following file:

File
----
12-3    John    121
 5-1    Sam     122

The file is tab(\t) delimited. I am loading the row as line:chararray as I want the data not to be split in individual fields.

And now, I want to pull and store the details (12-3, and 5-1) as separate data.

I am trying with STRSPLIT and REGEX_EXTRACT_ALL, but the data doesn't seem to match.

splitdata = FOREACH filedata {
    regex = REGEX_EXTRACT_ALL(line, '^([0-9]*)\\-([0-9]*)');
    split = STRSPLIT(line, '\\t', 1);
    GENERATE regex, split;
};

This is how I want my final data to be:

(12, 3, 12-3    John    121)
( 5, 1,  5-1    Sam     122)

回答1:

What about:

A = LOAD .... AS (line:chararray);
B = FOREACH A GENERATE FLATTEN(REGEX_EXTRACT_ALL(line, '^(.*)\t(.*)\t(.*)$')) 
      AS (id:chararray, name:chararray, nameid:chararray);
C = FOREACH B GENERATE FLATTEN(REGEX_EXTRACT_ALL(id, '^([0-9]*)\\-([0-9]*)')), 
      id, name, nameid;
STORE C INTO ...

If you would split the lines into fields along \t when loading, you could skip B = ...

回答2:

Thanks Lorand.

Since you gave a little idea about how to use the REGEX_EXTRACT_ALL, here is how I finally used it.

FOREACH A GENERATE FLATTEN(REGEX_EXTRACT_ALL(line, '^([0-9]*)\\-([0-9]*).*')) 
  AS (FIELD1:chararray, FIELD2:chararray), line;

Pretty interesting to know that Matcher.matches() fails for '^([0-9]*)\\-([0-9]*)' while works for '^([0-9]*)\\-([0-9]*).*'.

来源：https://stackoverflow.com/questions/13396778/strsplit-and-regex-extract-all-in-piglatin

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Hadoop

apache-pig