Merge two dictionaries and keep the values for duplicate keys in Python

Question

Let\'s suppose that I have two dictionaries:

dic1 =  { \"first\":1, \"second\":4, \"third\":8} 
dic2 =  { \"first\":9, \"second\":5, \"fourth\":3}

Answer 1

Create a new dictionary dic having for keys the keys of dic1 and dic2 and value an empty list, then iterate over dic1 and dic2 appending values to dic:

dic1 =  { "first":1, "second":4, "third":8} 
dic2 =  { "first":9, "second":5, "fourth":3}

dic = {key:[] for key in list(dic1.keys()) + list(dic2.keys())}

for key in dic1.keys():
    dic[key].append(dic1[key])

for key in dic2.keys():
    dic[key].append(dic2[key])