Comparing string to each value in row - NoneType not iterable

Anvil Q&A
1

how would I deal with None type in this case ? I have some blank cells in the database and I need to deal with it because I am getting NoneType error:

@anvil.server.callable
def search_order(query):
 
  result = app_tables.tasks.search()
  if query:
    result = [
      x for x in result
      if query in x['order_number']
      or query in x['order_description']
      or query in x['order_client']
      or query in x['order_note']
    ]
  return result
2

@jan.kyselak

It seems that you are testing your query against each column for a given row in the database.

If this is correct and you don’t want to get caught by a None, you could test your query against the values in a dictionary, and repeat this for each row.

For example,

rows=[dict(r) for r in app_tables.tasks.search()]
result=[r for r in rows if query in r.values()]

Does that work for you?

3 Likes
3

Calling dict() on a database row is rather slow in our current implementation (we’re working on it!).

But it’s actually simpler to use a neat feature of Python, namely the or operator. None is “falsy”, so for the expression A or B, if A is None, that expression will return B. So we use x['column'] or "" to return the value of the column (if it’s not None), or an empty string (if it is None).

Here’s what that would look like on your sample code:

@anvil.server.callable
def search_order(query):
 
  result = app_tables.tasks.search()
  if query:
    result = [
      x for x in result
      if query in (x['order_number'] or "")
      or query in (x['order_description'] or "")
      or query in (x['order_client'] or "")
      or query in (x['order_note'] or "")
    ]
  return result
5 Likes
4

ah great, I couln’t figure out how to write this :slight_smile:
I have also changed the way when creating new rows so if there is nothing I better insert ‘’

Thank you

2 Likes