{"id":179171,"date":"2012-07-16T23:31:17","date_gmt":"2012-07-17T06:31:17","guid":{"rendered":"http:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=179171"},"modified":"2018-12-18T11:20:56","modified_gmt":"2018-12-18T19:20:56","slug":"generating-a-multivalue-choice-list","status":"publish","type":"blog","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-desktop\/analytics\/generating-a-multivalue-choice-list","title":{"rendered":"Generating a multivalue choice list"},"author":4041,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","format":"standard","meta":{"_acf_changed":false,"_searchwp_excluded":""},"categories":[23341],"tags":[24321,24331],"industry":[],"product":[36991],"class_list":["post-179171","blog","type-blog","status-publish","format-standard","hentry","category-analytics","tag-geoprocessing","tag-modelbuilder","product-arcgis-desktop"],"acf":{"short_description":"Prerequisite Reading Generating a choice list from a field","flexible_content":[{"acf_fc_layout":"content","content":"

Prerequisite Reading<\/strong>
\nGenerating a choice list from a field<\/a><\/p>\n

This blog is an extension of the blog Generating a choice list from a field, explaining:<\/p>\n

How to create a\u00a0MULTIVALUE<\/strong>\u00a0parameter choice list from an input feature class\/table automatically. In this example, multiple input parameters from a choice list are then iterated through. \u00a0The model can be easily extended to carry out numerous analysis that require user selected input parameters.<\/p>\n

Data<\/strong>
\nDownload the data from\u00a0here<\/strong><\/a>.<\/p>\n

Understanding the model:<\/strong><\/p>\n

    \n
  1. Download an example script tool from\u00a0here<\/a>.<\/strong><\/li>\n
  2. Add<\/a>\u00a0the script tool to the model.<\/li>\n
  3. Expose<\/a>\u00a0the input parameters (input feature class, field, value) of the script tool in the model.<\/li>\n
  4. Make the input parameters\u00a0model parameter<\/a>.<\/li>\n
  5. Use as described in the example below:<\/li>\n<\/ol>\n

    In the following example, the user can define an input feature class (e.g.Bird Locations<\/em><\/strong>) and a field (e.g.\u00a0Type<\/em><\/strong>) to generate a value list, from the model tool dialog. The value list parameter is then populated with a choice list of all the unique values in the field. This list is a multivalue parameter i.e. you can select multiple values from the drop down list.<\/p>\n

    \"\"<\/a><\/p>\n

    The output of the script tool is the multivalue with all the selected value (e.g.\u00a0American Coot, Black Scoter, Canada Goose<\/em><\/strong>\u00a0and\u00a0Gadwall<\/em><\/strong>).\u00a0In the model provided, this multivalue output is then connected to the\u00a0Multivalue Iterator<\/a>\u00a0as input in the sub-model.\u00a0Learn more about model within a model\/sub-model.<\/a><\/p>\n

    \"\"<\/a><\/p>\n

    The tool then iterates over each value (e.g.\u00a0American Coot, Black Scoter, Canada Goose<\/em><\/strong>\u00a0and\u00a0Gadwall<\/em><\/strong>). The output of this iterator (Values\u00a0<\/em><\/strong>variable) is then input to the\u00a0Select<\/a>\u00a0tool as an inline variable, in the expression, to select features (\u201cType\u201d = \u2018%Value%\u2019<\/strong><\/em>).\u00a0Learn more about inline variable substitution<\/a>.<\/p>\n

    \"\"<\/a><\/p>\n

    The\u00a0Calculate Value<\/a>\u00a0tool is used to remove spaces in the selected values (e.g.\u00a0American Coot\u00a0<\/em><\/strong>changes to\u00a0AmericanCoot\u00a0<\/em><\/strong>(no space)) using the\u00a0.replace<\/em>\u00a0Python function.<\/p>\n

    \"\"<\/a><\/p>\n

    The output of the Calculate Value tool is then used as inline variable in the output of the Select tool (e.g. C:ScratchScratch.gdb%Name%).<\/p>\n

    \"\"<\/a><\/p>\n

    The\u00a0Collect Value<\/a>\u00a0tool is used to collect the output from all the iterations. The output of the Collect Value tool is made a\u00a0model parameter<\/a>\u00a0so that when the sub-model is added to the main model, the output of model parameter becomes a variable in the model.<\/p>\n

    To run the iterator and the Calculate Value tool before the Select tool two\u00a0preconditions<\/a>\u00a0are created:<\/p>\n

      \n
    1. From the output of the iterator to the Select tool.<\/li>\n
    2. From the output of the Calculate tool to the Select tool.<\/li>\n<\/ol>\n

      Tips:<\/strong><\/p>\n