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"Loop Parameters over a collection of strings"

arc12arc12 Member Posts: 3 Contributor I
edited May 2019 in Help
HI -
I can see how Loop Parameters works to loop over numerical values but I want to set a parameter with a string type.
Specifically, I want to set the URL parameter for the "Read RSS Feed" operation from a list of URLs,

I've experimented, googled and searched these email forums but got nowhere.

Is this possible somehow?

Cheers, Adam


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    ImageMinerImageMiner Member Posts: 4 Contributor I

    maybe read your urls from a file via "Read Excel" operator. Then make a "Loop Values" over the attribute holding the urls.
    Inside operator "Read RSS" use the macro %{loop_value} as value for "url".
    The name "loop_value" is defined inside the loop operator, so you can use self defined names, too.

    Hope this helps

  • Options
    arc12arc12 Member Posts: 3 Contributor I
    Thanks imageminer; that was just the info I needed. Simple when you know how!

    For the benefit of others, below is the XML for a how-to-do-it. NB I used the CSV reader, which requires metadata be set. The easiest way to get this right is to use the "wizard". In my case below there was a fist column with entries I discard.

    Cheers, Adam
    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    <process version="5.1.004">
      <operator activated="true" class="process" compatibility="5.1.004" expanded="true" name="Process">
        <process expanded="true" height="325" width="413">
          <operator activated="true" class="read_csv" compatibility="5.1.004" expanded="true" height="60" name="Read CSV" width="90" x="55" y="162">
            <parameter key="csv_file" value="[path to file]/feeds.csv"/>
            <parameter key="column_separators" value=","/>
            <parameter key="first_row_as_names" value="false"/>
            <list key="annotations">
              <parameter key="0" value="Name"/>
            <list key="data_set_meta_data_information">
              <parameter key="0" value="type.false.text.attribute"/>
              <parameter key="1" value="url.true.text.attribute"/>
          <operator activated="true" class="loop_values" compatibility="5.1.004" expanded="true" height="76" name="Loop Values" width="90" x="246" y="255">
            <parameter key="attribute" value="url"/>
            <process expanded="true" height="593" width="614">
              <operator activated="true" class="web:read_rss" compatibility="5.1.000" expanded="true" height="60" name="Read RSS Feed" width="90" x="112" y="147">
                <parameter key="url" value="%{loop_value}"/>
              <connect from_op="Read RSS Feed" from_port="output" to_port="out 1"/>
              <portSpacing port="source_example set" spacing="0"/>
              <portSpacing port="sink_out 1" spacing="0"/>
              <portSpacing port="sink_out 2" spacing="0"/>
          <connect from_op="Read CSV" from_port="output" to_op="Loop Values" to_port="example set"/>
          <connect from_op="Loop Values" from_port="out 1" 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"/>
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