DRY version of python if statements

Question

I am trying to do a database insert, with a table that has about twenty rows. The insert looks like this:

if not title.name:
    title.name = data['title']
if not title.synopsis:
    title.synopsis = data['synopsis']
...

Basically, I am updating the rows if they don't exist for every db column.

What would be a cleaner, more efficient way to do this?

Ned Batchelder · Accepted Answer · 2013-02-17 23:03:49Z

3

for column in ('name', 'synopsis', 'something', 'other'):
    if not getattr(title, column):
        setattr(title, column, data[column])

answered Feb 17, 2013 at 23:03

Ned Batchelder

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1 Comment

you should check if hasattr(title,column)

Rafal R · Accepted Answer · 2013-02-17 23:04:57Z

1

Use getattr and setattr functions:

for attribute in ['title', 'synopsis']:
   if not getattr(title, attribute):
       setattr(title, attribute, data[atribute])

You can read more about them here.

answered Feb 17, 2013 at 23:04

Rafal R

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6502 · Accepted Answer · 2013-02-18 08:01:36Z

1

You can use or:

title.name = title.name or data['title']
title.synopsis = title.synopsis or data['synopsis']

or alternatively you can do it dynamically:

for attr in data:
    if not getattr(title, attr):
        setattr(title, attr, data[attr])

answered Feb 17, 2013 at 23:04

6502

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If data is a dictionary, you don't need to use .keys(). Iterating over a dictionary iterates over its keys.