Python quirk I just learned and think is worth sharing. A missing valued doesn’t equal itself.
Here’s the context: I’m making a list of values from a column that could not be converted to a date. Missing values can’t be converted so they end up in the list (e.g. [nan, '7/5/21 for pass 2']. So how do we discard this empty value? We use a list comprehension to see if the value is equal to itself ( [val for val in my_list if val == val] ) and will get a nan free list.