How to add each consecutive element of an array into each element of a list of dictionaries?

Question

I have a list of dictionaries in the form:

mylist = [{1: 0.0, 2: 1.0, 3: 2.0},
          {1: 0.0, 2: 2.3, 3: 1.5},
          {1: 0.6, 2: 1.0, 3: 1.0}]

And a list of the form:

arr = [[1, 0, 0, 1],
       [1, 0, 2, 1],
       [1.0, 1.1, 3.5, 2.0]]

Length of arr is the same as that of mylist. How can I add each element of arr into their corresponding index elements in mylist so that after insertion, mylist is of the form:

mylist = [{1: 0.0, 2 : 1.0, 3: 2.0, 4: 1, 5: 0, 6: 0, 7: 1},
          {1:0.0, 2: 2.3, 3:1.5, 4: 1, 5: 0, 6: 2, 7: 1},
          {1: 0.6, 2: 1.0, 3: 1.0, 4: 1.0, 5: 1.1, 6: 3.5, 7: 2.0}]

So all dicts in `mylist` start with keys `1`, `2` and `3`? – Reaper Apr 29 '17 at 23:21 — Reaper, Apr 29 '17 at 23:21

Peter Wood · Accepted Answer · 2017-04-29T23:50:42.760

2

enumerate each sublist of arr, starting from 4, and update each dictionary.

You associate the relevant dictionary with the relevant list by zipping them together with zip:

for d, extra in zip(mylist, arr):
    d.update(enumerate(extra, start=4))

enumerate normally counts from 0:

>>> list(enumerate([1, 0, 0, 1]))
[(0, 1), (1, 0), (2, 0), (3, 1)]

You want it to count from 4:

>>> list(enumerate([1, 0, 0, 1], start=4))
[(4, 1), (5, 0), (6, 0), (7, 1)]

edited Apr 29 '17 at 23:50

answered Apr 29 '17 at 23:23

Peter Wood

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What is 4 here : length of mylist or arr ? – Saurav-- Apr 29 '17 at 23:31
The enumeration would normally start from `0`, but you want it to start from `4`, e.g. the first dictionary update is `{4: 1, 5: 0, 6: 0, 7: 1}` – Peter Wood Apr 29 '17 at 23:33

How to add each consecutive element of an array into each element of a list of dictionaries?

1 Answers1