CODEWITHSUNDEEP
pythonsorting
user7172
user7172

Reputation: 974

Sort list of dictionaries by another list

Sort list of dictionaries by another list. I have got list with dictionaries (IN) and I want to sort this by another list (sortValue).

IN = [{
        "id": "a", 
        "val": "Value", 
        "val1": "Value1"
 }, 
 {
        "id": "b", 
        "val": "Value", 
        "val1": "Value1"
 }, 
 {
        "id": "c", 
        "val": "Value", 
        "val1": "Value1"
 }]

sortValue = ['b','c','a']

I want the output 

OUT  = [{
        "id": "b", 
        "val": "Value", 
        "val1": "Value1"
    }, 
    {
        "id": "c", 
        "val": "Value", 
        "val1": "Value1"
    },
    {
        "id": "a", 
        "val": "Value", 
        "val1": "Value1"
    }]

How to get something like this?

I have tried:

OUT = []
for xx in sortValue:
    for x in IN:
        if x['id'] == xx:
            OUT.append(x)
print OUT
del OUT

But value in dict is mixed. [{'val1': 'Value1', 'id': 'b', 'val': 'Value'}, {'val1': 'Value1', 'id': 'c', 'val': 'Value'}, {'val1': 'Value1', 'id': 'a', 'val': 'Value'}]

Upvotes: 7

Views: 3131

Answers (2)

fredtantini
fredtantini

Reputation: 16556

You can also use the key parameter of the sorted function. In your case, you want the index of sortValue for the id of each item on the list:

>>> pprint(sorted(IN,key=lambda x:sortValue.index(x['id'])))
[{'id': 'b', 'val': 'Value', 'val1': 'Value1'},
 {'id': 'c', 'val': 'Value', 'val1': 'Value1'},
 {'id': 'a', 'val': 'Value', 'val1': 'Value1'}]

More on sorting with python on its wiki.

Upvotes: 19

BlackJack
BlackJack

Reputation: 4679

Build a dictionary that maps IDs to the dictionary with that ID and then go through your sortValue list and pick the dictionary for each ID value:

id2dict = dict((d['id'], d) for d in IN)
OUT = [id2dict[x] for x in sortValue]

Upvotes: 2

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