Copy value from a cell to another cell if it exists in another sheet's column

I made this sample code for Google Apps Script that can help you sort the information. I added some comments in case you want to modify some of the columns or cells working on it. Here is the code:

function Split_by_tags() {

  // Get the sheets you will work with by the name of the tab

  const ss_posts = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Posts Sheet");
  const ss_tags = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Tags Sheet");
  const ss_output = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Expected Output");

  // Get the range of the columns to of "Posts Sheet" we will work with
  // If range_1 is the ID, range 2 is the title, range 3 is tags
  // If you change the columns in the future, you only need to update this part

  let range_1 = ss_posts.getRange("A2:A").getValues().flat();
  let range_2 = ss_posts.getRange("B2:B").getValues().flat();
  let range_3 = ss_posts.getRange("C2:C").getValues().flat();
 
    // filter the arrays information to only the cells with values for "Posts Sheet"
  // This way, you can add new information to the tags rows and they will be added

  range_1 = range_1.filter((element) => {return (element !== '')});
  range_2 = range_2.filter((element) => {return (element !== '')});
  range_3 = range_3.filter((element) => {return (element !== '')});
 

  // The values we will compare the tags with in arrays

  let range_type = ss_tags.getRange("A2:A").getValues().flat();
  let range_location = ss_tags.getRange("B2:B").getValues().flat();
  let range_category = ss_tags.getRange("C2:C").getValues().flat();

  // filter the arrays information to only the cells with values for "Tags Sheet"
  // This way, you can add new information to the tags rows and they will be added 

  range_type = range_type.filter((element) => {return (element !== '')});
  range_location = range_location.filter((element) => {return (element !== '')});
  range_category = range_category.filter((element) => {return (element !== '')});

  // new Arrays where the information will be sort, I added a new tag option called "Other" 
  // just in case the information in the column 2 has a value which is not under "Tags Sheet"
  let type_tag = [];
  let location_tag = [];
  let category_tag = [];
  let other_tag = [];

  // for to copy the ID from "Posts Sheet" to "Expected Output"

  for (let i=0; i< range_1.length ; i++){
      ss_output.getRange(i+2,1).setValue(range_1[i]);    
    };

  // for to copy the title from "Posts Sheet" to "Expected Output"

  for (let j=0; j< range_2.length ; j++){
      ss_output.getRange(j+2,2).setValue(range_2[j]);    
    };

  // fuction to sort the tags from "Posts Sheet" base in "Tags Sheet" 

  function Separate_value(value_array){
      
    for (let k=0; k < value_array.length; k++){

      if(range_type.includes(value_array[k])){
        type_tag.push(value_array[k]);
      }
      else if(range_location.includes(value_array[k])){
        location_tag.push(value_array[k]);
      }
      else if(range_category.includes(value_array[k])){
        category_tag.push(value_array[k]);
      }
      else{
        other_tag.push(value_array[k]);
      }
                   
    };
  } 

  // Function to empty the arrays for the next loop

  function Empty_value(){
    type_tag = [];
    location_tag = [];
    category_tag = [];
    other_tag = []; 
  }

  // for to add the values we sorted to "Expected Output"
      
  for (let e=0; e < range_3.length; e++ ){
    let value_array = range_3[e].split(', ');  
    Separate_value(value_array)
    ss_output.getRange(e+2,3).setValue(type_tag.join(", "));
    ss_output.getRange(e+2,4).setValue(category_tag.join(", "));
    ss_output.getRange(e+2,5).setValue(location_tag.join(", "));
    ss_output.getRange(e+2,6).setValue(other_tag.join(", "));
    Empty_value();  
    
  };

}

You can bound the script by accessing Extensions > Apps Script in your Google Sheet.

Copy and paste the sample code, and run it. The first time you run the Apps Script, it will ask you for permissions, accept those, and the information will get sorted.

You can also add a trigger to the Apps Script so it can sort the information automatically when new data is added.

Reference:

• Create a bound Apps Script.
• Create trigger.