Apache pig 正则表达式提取Apache Pig中字符串的第一部分

我需要从下面的输入数据中提取邮政编码地区

AB55 4
DD7 6LL
DD5 2HI

我的代码

A = load 'data' as postcode:chararray;
B = foreach A {
code_district = REGEX_EXTRACT(postcode,'<SOME EXP>',1);
generate code_district;
};
dump B;

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提取字符串第一部分的正则表达式应该是什么？

可以尝试下面的正则表达式吗

选项1:

A = LOAD 'input' as postcode:chararray;
code_district = FOREACH A GENERATE REGEX_EXTRACT(postcode,'(\\w+).*',1);
DUMP code_district;

A = LOAD 'input' as postcode:chararray;
code_district = FOREACH A GENERATE REGEX_EXTRACT(postcode,'([a-zA-Z0-9]+).*',1);
DUMP code_district;

(AB55)
(DD7)
(DD5)

选项2:

A = LOAD 'input' as postcode:chararray;
code_district = FOREACH A GENERATE REGEX_EXTRACT(postcode,'(\\w+).*',1);
DUMP code_district;

A = LOAD 'input' as postcode:chararray;
code_district = FOREACH A GENERATE REGEX_EXTRACT(postcode,'([a-zA-Z0-9]+).*',1);
DUMP code_district;

(AB55)
(DD7)
(DD5)

输出：

A = LOAD 'input' as postcode:chararray;
code_district = FOREACH A GENERATE REGEX_EXTRACT(postcode,'(\\w+).*',1);
DUMP code_district;

A = LOAD 'input' as postcode:chararray;
code_district = FOREACH A GENERATE REGEX_EXTRACT(postcode,'([a-zA-Z0-9]+).*',1);
DUMP code_district;

(AB55)
(DD7)
(DD5)

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这不适用于非ASCII字符。ISO-8859-9