Notes supporting issue #256.



In [1]:

    
import petl.interactive as etl



In [2]:

    
t1 = etl.wrap([['foo', 'bar'], [1, 'a'], [2, 'b']])
t1









    Out[2]:







foo
bar




1
a


2
b



In [3]:

    
t2 = etl.wrap([['foo', 'bar'], [1, 'a'], [2, 'c']])
t2









    Out[3]:







foo
bar




1
a


2
c



In [5]:

    
t3 = etl.merge(t1, t2, key='foo')
t3









    Out[5]:







foo
bar




1
a


2
Conflict(['c', 'b'])

The problem with the above is that you cannot tell from inspecting t3 alone which conflicting value comes from which source.

A workaround as suggested by @pawl is to use the conflicts() function, e.g.:



In [9]:

    
t4 = (etl
    .cat(
        t1.addfield('source', 1),
        t2.addfield('source', 2)
    )
    .conflicts(key='foo', exclude='source')
)
t4









    Out[9]:







foo
bar
source




2
b
1


2
c
2