How to use convert with custom function and reference row

[carlcorder]

Would it be possible to get an example placed in the documentation of using convert with a custom function that has reference to the row? I assume something like this should work?

table = [[a,b,c], [1,2,3]]

def my_func(row):
    return row['b'] + row['c']
    
etl.convert(table, 'a', my_func)

# [[a,b,c], [5,2,3]]

[juarezr]

Hi @carlcorder ,

Looks good to me.

Would you consider making a PR adding an example in the convert function documentation ?
I would be happy to review and integrate your proposal.

[javidy]

Hi @juarezr ,

I'd be happy to help with this issue. Can I take this forward?

[juarezr]

Sure.
Please, tell me if you would have any questions.

[carlcorder]

Thanks @javidy! I forgot that I also need to pass the pass_row=True keyword in order for the above to work.

[javidy]

Thanks @carlcorder for comment. I'll take that into account.

[javidy]

For some reason I couldn't get it worked. When I try below code, I get None instead of sum of fields.
Could you please check if I miss anything?

import petl as etl

def my_func(row):
    return row.bar + row.baz
    #row['bar'] + row['baz']

table1 = [['foo', 'bar', 'baz'], ['A', 2.4, 12]]

table2 = etl.convert(table1, 'foo', my_func, pass_row=True)

Here is the screenshot

[carlcorder]

Hey Javidy, my hunch is that my_func is not getting called. I think the issue here is that the signature of the function needs to be def my_func(val, row): ?

[javidy]

hey @carlcorder ,

you're right about that. It works when I change the signature of the function.

thanks for help :)