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How select sub-vectors from a vectors in RapidMiner?

GDUFSGDUFS Member Posts: 1 Newbie
edited May 2021 in Help
There is a column vector V=[v1, v2, ..., vt], I desire to select all vectors but last vector, so how can I do?

[v1, v2, ..., v_t]  ==extract==> [v1, v2, ..., v_t-1]


Best Answer

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    BalazsBaranyBalazsBarany Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert Posts: 955 Unicorn
    Solution Accepted
    Hi,

    does this column contain the elements as a string, in a reliable, standard format?

    If yes, the easiest way would be a regular expression replacement using Replace.

    <?xml version="1.0" encoding="UTF-8"?><process version="9.9.000">
      <context>
        <input/>
        <output/>
        <macros/>
      </context>
      <operator activated="true" class="process" compatibility="9.9.000" expanded="true" name="Process">
        <parameter key="logverbosity" value="init"/>
        <parameter key="random_seed" value="-1"/>
        <parameter key="send_mail" value="never"/>
        <parameter key="notification_email" value=""/>
        <parameter key="process_duration_for_mail" value="30"/>
        <parameter key="encoding" value="SYSTEM"/>
        <process expanded="true">
          <operator activated="true" class="utility:create_exampleset" compatibility="9.9.000" expanded="true" height="68" name="Create ExampleSet" width="90" x="112" y="34">
            <parameter key="generator_type" value="comma separated text"/>
            <parameter key="number_of_examples" value="100"/>
            <parameter key="use_stepsize" value="false"/>
            <list key="function_descriptions"/>
            <parameter key="add_id_attribute" value="false"/>
            <list key="numeric_series_configuration"/>
            <list key="date_series_configuration"/>
            <list key="date_series_configuration (interval)"/>
            <parameter key="date_format" value="yyyy-MM-dd HH:mm:ss"/>
            <parameter key="time_zone" value="SYSTEM"/>
            <parameter key="input_csv_text" value="vector&#10;[v_1, v_2, v_t-1, v_t]&#10;[v_1, v_2, v_3, v_4, v_5, v_6]"/>
            <parameter key="column_separator" value=";"/>
            <parameter key="parse_all_as_nominal" value="false"/>
            <parameter key="decimal_point_character" value="."/>
            <parameter key="trim_attribute_names" value="true"/>
          </operator>
          <operator activated="true" class="replace" compatibility="9.9.000" expanded="true" height="82" name="Replace" width="90" x="313" y="34">
            <parameter key="attribute_filter_type" value="single"/>
            <parameter key="attribute" value="vector"/>
            <parameter key="attributes" value=""/>
            <parameter key="use_except_expression" value="false"/>
            <parameter key="value_type" value="nominal"/>
            <parameter key="use_value_type_exception" value="false"/>
            <parameter key="except_value_type" value="file_path"/>
            <parameter key="block_type" value="single_value"/>
            <parameter key="use_block_type_exception" value="false"/>
            <parameter key="except_block_type" value="single_value"/>
            <parameter key="invert_selection" value="false"/>
            <parameter key="include_special_attributes" value="false"/>
            <parameter key="replace_what" value="\[(.+), *[^,]+\]"/>
            <parameter key="replace_by" value="[$1]"/>
          </operator>
          <connect from_op="Create ExampleSet" from_port="output" to_op="Replace" to_port="example set input"/>
          <connect from_op="Replace" from_port="example set output" to_port="result 1"/>
          <portSpacing port="source_input 1" spacing="0"/>
          <portSpacing port="sink_result 1" spacing="0"/>
          <portSpacing port="sink_result 2" spacing="0"/>
        </process>
      </operator>
    </process>


    In the example process I keep everything up until the last comma. If the structure of your data is different, you might want to change the regular expression.

    Replace what: \[(.+), *[^,]+\]
    Replace by: [$1]

    Regards,
    Balázs
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