Applying TRIM() in Pig for all fields in a tuple

问题

I am loading a CSV file with 56 fields. I want to apply TRIM() function in Pig for all fields in the tuple.

I tried:

B = FOREACH A GENERATE TRIM(*);

But it fails with below error-

ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1045: Could not infer the matching function for org.apache.pig.builtin.TRIM as multiple or none of them fit. Please use an explicit cast.

Please help. Thank you.

回答1:

To Trim a tuple in the Pig, you should create a UDF. Register the UDF and apply the UDF with Foreach statement to the field of the tuple you want to trim. Below is the code for trimming the tuple with UDF.

public class StrTrim extends EvalFunc<String> {
    public String exec(Tuple input) throws IOException {
        if (input == null || input.size() == 0)
            return null;
        try {
            String str = (String)input.get(0);
            return str.trim();
        }
        catch(Exception e) {
            throw WrappedIOException.wrap("Caught exception processing input row ", e);
        }
    }
}

来源：https://stackoverflow.com/questions/29413674/applying-trim-in-pig-for-all-fields-in-a-tuple