How can one sort a list of dictionaries into an excel sheet such that each unique key and one corresponding key are placed into columns

Question

I have a list of dictionaries organized as such:

listofdictionaries = [{'key1': (A, B, C), 'key2':[1, 2, 3]}, 
                      {'key1': (AA, BB, CC), 'key2':[1, 2, 3]}, 
                      {'key1': (AAA, BBB, CCC), 'key2':[4, 5, 6]}]

The first and second items on this list have the same value for the key2. A different value for key2 is present in the third item. I want the columns arranged as follows using Python:

Group 1	Group 1 Items	Group 2	Group 2 Items
[1, 2, 3]	(A, B, C)	[4, 5, 6]	(AAA, BBB, CCC)
	(AA, BB, CC)

In addition, I would like the output to be a .csv file.

Answer 1

With pandas, you can use something like this function

def groupItems(dictList, itemsFrom, groupBy, saveTo=None):
    ik, gk, colsDict = itemsFrom, groupBy, {}
    groups = {str(d.get(gk)): d.get(gk) for d in dictList} 
    itemsList = [ [d.get(ik) for d in dictList if str(d.get(gk))==g] 
                  for g in groups   ]

    maxRows = max(len(li) for li in itemsList) if groups else 0
    for gi, (g, li) in enumerate(zip(groups.keys(), itemsList), 1):
        colsDict[f'Group {gi}'] = [groups[g]] + [None]*(maxRows-1)
        colsDict[f'Group {gi} Items'] = li + [None]*(maxRows-len(li))
    
    rdf = pandas.DataFrame(colsDict)
    if saveTo and isinstance(saveTo, str):
        print('Saving', maxRows, 'rows for', len(groups),'groups to', saveTo)
        rdf.to_csv(saveTo, index=False)
    return rdf

Calling groupItems(listofdictionaries, 'key1', 'key2', 'x.csv') will save the DataFrame from the screenshot below to x.csv.

 _{To demonstrate that the brackets were not lost:}