"Regular Expression search"

Railsman

Hi all,

I am trying to filter rows in a dataset that contain characters such as ' | and @. Which operator is best suited to this and also how would this regular expression be be written?

Thanks in advance.

haddock

Greetings Railsman!

In the following I generate examples with value1..value10 as attribute values throughout. Then value1 and value2 have the offending characters inserted. Finally a regex replacement finds those edits and sets them to missing values, and examples with missing values are trashed.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.0">
  <context>
    <input>
      <location/>
    </input>
    <output>
      <location/>
      <location/>
    </output>
    <macros/>
  </context>
  <operator activated="true" class="process" expanded="true" name="Process">
    <process expanded="true" height="341" width="815">
      <operator activated="true" class="generate_nominal_data" expanded="true" height="60" name="Generate Nominal Data" width="90" x="45" y="30">
        <parameter key="number_of_values" value="10"/>
      </operator>
      <operator activated="true" class="replace" expanded="true" height="76" name="Insert |" width="90" x="246" y="75">
        <parameter key="replace_what" value="value1"/>
        <parameter key="replace_by" value="val|ue1"/>
      </operator>
      <operator activated="true" class="replace" expanded="true" height="76" name="Insert @ width=90" x="380" y="75">
        <parameter key="replace_what" value="value2"/>
        <parameter key="replace_by" value="@value2"/&gt;
      </operator>
      <operator activated="true" class="replace" expanded="true" height="76" name="Replace | or @ width=90" x="581" y="120">
        <parameter key="replace_what" value=".*@.*|.*\|.*"/>
      </operator>
      <operator activated="true" class="filter_examples" expanded="true" height="76" name="Filter Examples" width="90" x="715" y="165">
        <parameter key="condition_class" value="no_missing_attributes"/>
      </operator>
      <connect from_op="Generate Nominal Data" from_port="output" to_op="Insert |" to_port="example set input"/>
      <connect from_op="Insert |" from_port="example set output" to_op="Insert @ to_port=example set input"/>
      <connect from_op="Insert @ from_port=example set output" to_op="Replace | or @ to_port=example set input"/>
      <connect from_op="Replace | or @ from_port=example set output" to_op="Filter Examples" to_port="example set input"/>
      <connect from_op="Filter Examples" from_port="example set output" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="198"/>
      <portSpacing port="sink_result 2" spacing="90"/>
    </process>
  </operator>
</process>

If you play around with the ( new in V5 ) regex parameter editor you'll soon see just how useful, but impenetrable, regex can be.

Railsman

Cool thanks Haddock!

I have some experience with the old RapidMiner  versions and am still getting to grips with V5, but its a marvelous tool.