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pythondictionarymap-function

How do I reduce list of dictionaries

I have a list of dictionaries in python. For example

mylist = [
    {'a': 'x', 'b':'y', 'c':'z'},
    {'a':'e','b':'f','c':'g'},
    {'a':'h','b':'i','c':'j'}
]

how can i map this into

mynewlist = [
    {'a':'x'},
    {'a','e'},
    {'a':'h'}
]

And

mynewlist2 = [
    {'a':'x','b':'y'},
    {'a','e','b':'f'},
    {'a':'h','b':'i'}
]
Solution

  • You can use list comprehension to do this:

    mynewlist = [{'a': item['a']} for item in mylist]

    Loop over the list and just grab the a value from the dict. For mynewlist2, just do the same thing, but with 2 values:

    mynewlist2 = [{'a': item['a'], 'b': item['b']} for item in mylist]