Creating a list of dictionaries from a list of lists in Python

Question

My question is on how to create a list of dictionaries from a list of lists, and is a deviation from this question Dict Comprehension python from list of lists and this question List of Lists to List of Dictionaries

I have a very long pandas data frame with latitudes and longitudes as such

     LAT        LON
     40         5
     40         6
     41         5
     42         8
     42         9

I managed to transform it into a list of lists with towers.values(towers is the name of the dataframe) in which each list is of the format [lat,lon]

My goal is to have

list_dict = [{'lat': 40, 'lon': 5}, 
             {'lat': 40, 'lon': 6}, 
             {'lat': 41, 'lon': 5},
             {'lat': 41, 'lon': 5},
             {'lat': 42, 'lon': 8},
             {'lat': 42, 'lon': 9}]

How can I do this?

Off the top of my head, try `towers.to_dict(orient='records')` — Alex Hall, Sep 01 '19 at 08:55

ComplicatedPhenomenon · Accepted Answer · 2019-09-01T09:45:50.783

2

list_dict = [{'lat': df.loc[i, 'Lat'], 'lon' : df.loc[i, 'Lon']} for i in range(df.shape[0])]

As @yatu proposed, It's much more efficient to use the df.loc than a chained index.

data = zip(df['Lat'].tolist(), df['Lon'].tolist())
[{'lat': a, 'lon': b} for a, b in data]

edited Sep 01 '19 at 09:45

answered Sep 01 '19 at 09:06

ComplicatedPhenomenon

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Chained indexing is discouraged in the docs https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy – yatu Sep 01 '19 at 09:10
1

@yatu Good idea. – ComplicatedPhenomenon Sep 01 '19 at 09:43

score 0 · Answer 2 · answered Sep 01 '19 at 09:12

0

Iterating over each row of dataframe can give the solution.

res_list_of_dict = [{'lat':i[1][0], 'long':i[1][1]} for i in df.iterrows()]

answered Sep 01 '19 at 09:12

Akash Pagar

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Creating a list of dictionaries from a list of lists in Python

2 Answers2