pandas DataFrame的dicts列表列表

Question

I have a large list of a list of dicts, that I would like to transform into a pandas DataFrame. Below I have made a small example of my variable, but in reallity the outer list is much larger and each of the inner lists has more dictionaries.

all_meta = [[{"Person":1}, {"trial":2}, {"b-setting":"Off"}], 
            [{"Person":2}, {"trial":5}, {"b-setting":"Off"}],
            [{"Person":2}, {"trial":6}, {"b-setting":"Off"}],
            [{"Person":2}, {"trial":7}, {"b-setting":"Off"}, {"ERROR":"error2"}]
           ]

I want a Pandas DataFrame that looks like this:

    person    trial    b-setting    ERROR
0        1        2          Off     None
1        2        5          Off     None
2        2        6          Off     None
3        2        7          Off   error2

I've tried:

In[1]: pd.DataFrame(all_meta)
Out[1]: 
               0             1                     2                    3
0  {'Person': 1}  {'trial': 2}  {'b-setting': 'Off'}                 None
1  {'Person': 2}  {'trial': 5}  {'b-setting': 'Off'}                 None
2  {'Person': 2}  {'trial': 6}  {'b-setting': 'Off'}                 None
3  {'Person': 2}  {'trial': 7}  {'b-setting': 'Off'}  {'ERROR': 'error2'}

Is there a way to create an empty DataFrame and then append each inner list?

Or how would I only get the values in the DataFrame and the keys in the Column names?

Answer 1

try this:

def merge_dicst(dlist):
    d = {}
    for x in dlist:
        d.update(x)
    return d

In [97]: pd.DataFrame([merge_dicst(x) for x in all_meta])
Out[97]:
    ERROR  Person b-setting  trial
0     NaN       1       Off      2
1     NaN       2       Off      5
2     NaN       2       Off      6
3  error2       2       Off      7