I have a list of columns and records that I get by using DATA-API RDS execute_statement using boto3. As the way the api responds it difficult to get the data out in a psycopg2 RealDictCursor format to insert into another database. What I want to do is illustrated below.
columns = ["a","b","c"]
records = [[1,2,3],[4,5,6]]
I want to convert this to a dictionary that represents it like
[{"a":1,"b":2,"c":3},{"a":4,"b":5,"c":6}]
Do it like this:
Python 3.8.9 (default, Aug 3 2021, 19:21:54)
[Clang 13.0.0 (clang-1300.0.29.3)] on darwin
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>>> columns = ["a","b","c"]
>>> records = [[1,2,3],[4,5,6]]
>>> [dict(zip(columns,rec)) for rec in records]
[{'a': 1, 'b': 2, 'c': 3}, {'a': 4, 'b': 5, 'c': 6}]
>>>
How it works
Work from the outside in. [...] means we'll produce a list. x for rec in records means we will evaluate the part in x once for every element in records. zip(columns,rec) zips together the column names and rec, which will be an element from records. So, zip(['a','b','c'],[1,2,3]) produces the list ('a',1), ('b',2), ('c',3), which are the things we want to build the dict from. And, if you pass a list of 2-tuples to the dictionary constructor, it is happy to create a dictionary from it. ('a',1) becomes {'a':1,...}