Fetching characters through substring

abcd.efg.plan.1006746 abcder.fgds.dsdddf.212122s   Hi All, Suppose this is the  format of the name I am receiving through front end form.  I only want to fetch ‘plan’ through it?  Occurence of characters are not fixed. So I want to fetch the letters after second occurrence of ‘ . ‘ and all the characters before third occurrence of ‘ . ‘ in my file name.   This is what I have done: [DocumentType= 'Meta_Data_File'][Name=$Variable)]   I am checking whether the document type = meta is present and than to take the substring of document name from the front end text box. I got some suggestion about creating a variable and using substring and contains but I am really confused.  
2 answers

Assuming you have the file name in a string variable, now we can use string function to achieve the desired substring.
Use find(filename, '.') to find the index of first occurrence of “.” in the string. After this substring(filename, indexOfFirstDot) gives you the remaining string. 
Repeat this way to find the indices of your second “.” and third “.”
Now you can simply get the required portion of the string with something like 

substring(filename, secondDotIndex, thirdDotIndex-secondDotIndex)

Again, asking the same question a third time doesn’t work ;-)

See my new comment in your original post: https://forum.mendix.com/link/questions/103039

Also, you are using an XPAth, which is about retrieving data from the database, while you want to extract a substring from already available data. In that case you need to use (microflow) expressions → see my answers in your first post