Question

I am trying to build a function in python that yields values of two dictionaries IF a particular value from dict1 matches a particular value of dict2. My function looks like this:

def dict_matcher(dict1, dict2, item1_pos, item2_pos):
"""Uses a tuple value from dict1 to search for a matching tuple value in dict2. If a match is found, the other values from dict1 and dict2 are returned."""
for item1 in dict1:
    for item2 in dict2:
        if dict1[item1][item1_pos] == dict2[item2][item2_pos]:
            yield(dict1[item1][2], dict2[item2][6])

I am using dict_matcher like this:

matches = [myresults for myresults in dict_matcher(dict1, dict2 , 2, 6)]
print(matches)

When I print matches I get a list of correctly matching dict1 and dict2 values like this:

[('frog', 'frog'), ('spider', 'spider'), ('cricket', 'cricket'), ('hampster', 'hampster')]

How can I add variable arguments to this function so that, in addition to printing the matching values from each dictionary, I can also print the other values of each dictionary item in instances where dict1[item1][2] and dict2[item2][6] match? Can I use *args? Thanks for the help.

EDIT:
Ok, there seems to be some confusion as to what I am trying to do so let me try another example.

dict1 = {1: ('frog', 'green'), 2: ('spider', 'blue'), 3: ('cricket', 'red')}

dict2 = {a: ('frog', 12.34), b: ('ape', 22.33), c: ('lemur', 90.21)}

dict_matcher(dict1, dict2, 0, 0) would find matching values for value[0] from dict1 and value[0] from dict2. In this case, the only match is ‘frog’. My function above does this. What I am trying to do is extend the function to be able to print out other values from the dictionary items where dict1[value][0] == dict2[value][0] I want this to be specified in the function argument.

Answer 1

You said you’re calling it as

matches = [myresults for myresults in dict_matcher(dict1, dict2 , 2, 6)]

You should be calling it as

matches = list(dict_matcher(dict1, dict2 , 2, 6))

and it’s signature is

def dict_matcher(dict1, dict2, item1_pos, item2_pos, *args):

So 4 arguments passed, and 4 named arguments. So *args results in args = None.

I’m not sure exactly what you want, but if you do

yield dict1[item1][item1_pos], dict2[item2][item2_pos]

You’ll get the same thing as you get from doing

yield dict1[item1][2], dict2[item2][6]

If you want to get the whole matching items, do

yield dict1[item1], dict2[item2]

If you want to get one item from each, but not the matching item, do

def dict_matcher(dict1, dict2, item1_pos, item2_pos, other1_pos, other2_pos):

and

yield dict1[item1][other1_pos], dict2[item2][other2_pos]

and

matches = list(dict_matcher(dict1, dict2 , 2, 6, 3, 8)) 

or whatever instead of 3 and 8.

If you want to get several, but not all items, do

def dict_matcher(dict1, dict2, item1_pos, item2_pos, other1_poss, other2_poss):

and

yield [dict1[item1][i] for i in other1_poss], [dict2[item2][i] for i in other2_poss]

and

matches = list(dict_matcher(dict1, dict2 , 2, 6, (2, 3), (6, 8))) 

or whatever instead of [2, 3] and [3, 8].

If this isn’t what you meant, let me know.