Control Flow Collections

Conditionally add or skip elements when building lists and maps

When building lists and maps, the Expression language allows you to use the special control flow statement addif to conditionally add or skip elements.

[addif(true) 1, 2, 3] 
# Results in [1, 2, 3]

[addif(false) 1, 2, 3]
# Results in [2, 3]

This syntax also works with maps:

['a': 1, addif(true) 'b': 2, 'c': 3]
# Results in {'a': 1, 'b': 2, 'c': 3}

['a': 1, addif(false) 'b': 2, 'c': 3]
# Results in {'a': 1, 'c': 3}

Let's look at a more complex example. Let's say you want to build a map with contact information, but only add keys for fields that are not empty:

Query(Contact[Name, Email, Phone]) 
    ->  MAP({
        "name": Name,
        addif(NOT(ISBLANK(Email))) "email": Email,
        addif(NOT(ISBLANK(Phone))) "phone": Phone
    })