If the loop is too old please create a new post for your query.
For your question there are multiple ways to check if a string value exists in datatable,
- using select statement: if you know the column name you can use dt.select("[ColName] = ‘"+stringValue+"’"), this will give you array of data rows and you can convert back to table using .copytodatatable in the same select query.
- if you don’t know the column then you can use look up range activity: give the string input and then sheetname where you need to search and output will be the cell address of the first occurance, if there is no string present in the datatable then the output will be null.
Let us kno if this helps.