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copied!<p>It looks like what you really need is dictionaries, rather than arrays. If you use a dictionary, this problem becomes a whole lot easier. Converting to dicts couldn't be easier: </p> <pre><code>dictOne = dict(arrayOne) dictTwo = dict(arrayTwo) </code></pre> <p>From there, you can put them together like this:</p> <pre><code>combined = dict() for name in set(dictOne.keys() + dictTwo.keys()): combined[name] = [ dictOne.get(name, 0), dictTwo.get(name, 0) ] </code></pre> <p>What this does is create a new dictionary called <code>combined</code>, which we'll put the final data in. Then, we make a set of keys from both original dictionaries. Using a set ensures we don't do anything twice. Finally, we loop through this set of keys and add each pair of values to the <code>combined</code> dictionary, telling calls to the <code>.get</code> method to supply <code>0</code> if no value is present. If you need to switch the combined dictionary back to an array, that's pretty easy too: </p> <pre><code>arrayResult = [] for name in combined: arrayResult.append([ name ] + combined[name]) </code></pre> <p>Supposing you want to add another column to your result dictionary, all you have to do is change the middle code to look like this:</p> <pre><code>combined = dict() for name in set(dictOne.keys() + dictTwo.keys() + dictThree.keys()): combined[name] = [ dictOne.get(name, 0), dictTwo.get(name, 0), dictThree.get(name, 0) ] </code></pre> <p>If you wanted to encapsulate all this logic in a function (which is something I would recommend), you could do it like this:</p> <pre><code>def combine(*args): # Create a list of dictionaries from the arrays we passed in, since we are # going to use dictionaries to solve the problem. dicts = [ dict(a) for a in args ] # Create a list of names by looping through all dictionaries, and through all # the names in each dictionary, adding to a master list of names names = [] for d in dicts: for name in d.keys(): names.append(name) # Remove duplicates in our list of names by making it a set names = set(names) # Create a result dict to store results in result = dict() # Loop through all the names, and add a row for each name, pulling data from # each dict we created in the beginning for name in names: result[name] = [ d.get(name, 0) for d in dicts ] # Return, secure in the knowledge of a job well done. :-) return result # Use the function: resultDict = combine(arrayOne, arrayTwo, arrayThree) </code></pre>

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