How to filter not null data from list of dictionary ?

Typically you'd conduct a 2-stage process in your expression:

1. loop through each of the items in your array, examine each and where the 'name' is null, return null, other wise return the whole item. You can do this using a!forEach()
2. on the result from 1. use fn!reject() to remove all of the values that are now null

Here's the full code:

a!localVariables(
  local!myArray: {
    { name: "Aish", category: "A" },
    { name: "Jenny", category: "A" },
    { name: "", category: "C" },
    { name: "", category: "E" },
    { name: "", category: "E" }
  },
  fn!reject(
    fn!isnull,
    a!forEach(
      items: local!myArray,
      expression: if(fv!item.name = "", null, fv!item)
    )
  )
)

...and the result is:

Thanks a lot

Since I loathe the the old looping functions with a fiery passion these days, I would recommend just utilizing a!forEach() for the heavy lifting here.  The trick is, have it return an empty set instead of NULL, which in normal circumstances will not be returned as a member of the resulting array.  The one corner case is, for some quirky reason if all items are filtered out, then the result ends up returning a list of empty sets equal in length to the original list, but a!flatten takes care of this handily.

a!localVariables(
  local!myArray: {
    { name: "Aish", category: "A" },
    { name: "Jenny", category: "A" },
    { name: "", category: "C" },
    { name: "", category: "E" },
    { name: "", category: "E" }
  },
  
  a!flatten( 
  /* (a!flatten only becomes necessary when the filter would
      cause zero results to be returned) */
    a!forEach(
      items: local!myArray,
      expression: if(
        isnull(fv!item.name),
        {},
        fv!item
      )
    )
  )
  
  /*fn!reject(*/
    /*fn!isnull,*/
    /*a!forEach(*/
      /*items: local!myArray,*/
      /*expression: if(fv!item.name = "", null, fv!item)*/
    /*)*/
  /*)*/
)

Great! Thank you for your answer!