Only add to a dict if a condition is met

Question

I am using urllib.urlencode to build web POST parameters, however there are a few values I only want to be added if a value other than None exists

Answer 1

You can deal with all optional items using a single condition by using a dictionary comprehension:

apple = "red"
orange = None
dictparams = {
    key: value for key, value in
    {
        "apple": apple,
        "orange": orange
    }.items()
    if value is not None
}

The dictparams result will not contain "orange" in this case, because orange is None:

{'apple': 'green'}