Looking for a more pythonic way to merge a list full of dictionaries into one?

Question

I have a list with a bunch of dictionaries that I am trying to combine into one

Looks like this...

[{'name':'name', 'value':'john'}, {'name':'sex', 'value':'male'}, {'name':'color', 'value':'blue'}, {'name':'car', 'value':'toyota'}, {'name':'job', 'value':'cashier'}]

I'm trying to combine them all into one dictionary so that the name value is the key and the value is the value. Right now I'm doing something like this and it works fine but I know there is an easier way

keys = []
vals = []

for item in a:
    if item['name']:
        keys.append(item['name'])

    if item['value']:
        vals.append(item['value'])

md = dict(zip(keys,vals))

Any guidance would be appreciated... thank you

Perhaps, you can have a look at https://stackoverflow.com/questions/1781571/how-to-concatenate-two-dictionaries-to-create-a-new-one-in-python — dvlper, Mar 25 '20 at 02:01
Does this answer your question? [How do I merge two dictionaries in a single expression?](https://stackoverflow.com/questions/38987/how-do-i-merge-two-dictionaries-in-a-single-expression) — AMC, Mar 25 '20 at 02:37

score 5 · Accepted Answer · answered Mar 25 '20 at 01:45

5

You can use a dict comprehension.

new = {i['name']:i['value'] for i in a}

answered Mar 25 '20 at 01:45

xkcdjerry

965
4
15

Yep, that did it. Thanks – Austin not from Boston Mar 25 '20 at 02:46

score 3 · Answer 2 · answered Mar 25 '20 at 01:47

3

Assuming your list of dictionaries is called dict_list you can use dict comprehension as below:

new_dict = { dict['name'] : dict['value'] for dict in dict_list}

answered Mar 25 '20 at 01:47

katardin

596
3
14

3

It's a bad idea to use the names of built-in classes as variable names (dict) in this case it should not matter but it is a bad habit – Iain Shelvington Mar 25 '20 at 01:51
1

Good comment, I was just trying to make it blindingly obvious what object each step in the comprehension was trying to do (easy to get confused with abstractly named temp variables) – katardin Mar 25 '20 at 01:56

Austin · Answer 3 · 2020-03-25T01:58:20.960

1

You can directly use dict.values() for your specific case as keys and values are available in an order:

dict(d.values() for d in a)

edited Mar 25 '20 at 01:58

answered Mar 25 '20 at 01:53

Austin

25,759
4
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Assuming that all the dictionaries have the name and value entries in the correct order – Iain Shelvington Mar 25 '20 at 01:55

score 0 · Answer 4 · answered Mar 25 '20 at 05:33

You can do something like this also.

input_dict_list = [{'name':'name', 'value':'john'}, {'name':'sex', 'value':'male'}, {'name':'color', 'value':'blue'}, {'name':'car', 'value':'toyota'}, {'name':'job', 'value':'cashier'}]

out_put_dict = {}
for input_dict in input_dict_list:
    out_put_dict[input_dict['name']] = input_dict['value']

print(out_put_dict)

Looking for a more pythonic way to merge a list full of dictionaries into one?

4 Answers4