将数据框中的字典列表转换为 CSV

Question

I have a dataframe that looks like this (df1):

id  detail
78  [{}{}{}{}{}]
120 [{}{}{}{}{}]
110 [{}{}{}{}{}]
109 [{}{}{}{}{}]
109 [{}{}{}{}{}]
79  [{}{}{}{}{}]

The detail column contains a list of dictionaries and each dictionary looks like this:

{'y1': 549, 'score': 1, 'x2': 630, 'frame': 1054, 'y2': 564, 'x1': 602, 'visibility': 0.0, 'class': 5}

I need to extract this information into a CSV with this format:

frame, id, x1, y1, x2, y2, score, class, visibility

In addition, the x2 and y2 in the extracted data should be like this:

x2_new = x2 + x1 = 630 + 602 = 1232
y2_new = y2 + y1 = 564 + 549 = 1113

Expected output (Assuming the dict provided is in the first row of df1):

1054, 78, 602, 549, 1232, 1113, 1, 5, 0.0

I have tried this code to create a new df based off the detail column but I got an error:

for i in finaldftoconvert['id']:
    for k in finaldftoconvert[['detail'][['id']==i]]:
        df = pd.DataFrame(k)
print df

Error:

main.py:267: FutureWarning: elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison
  for k in finaldftoconvert[['detail'][['id']==i]]:
Traceback (most recent call last):
  File "main.py", line 268, in <module>
    df = pd.DataFrame(k)
  File "/usr/lib/python2.7/dist-packages/pandas/core/frame.py", line 305, in __init__
    raise PandasError('DataFrame constructor not properly called!')
pandas.core.common.PandasError: DataFrame constructor not properly called!

Answer 1

a = pd.DataFrame(index=[78],columns=["detail"])
a.loc[78,"detail"] = [{'y1': 549, 'score': 1, 'x2': 630, 'frame': 1054, 'y2': 564, 'x1': 602, 'visibility': 0.0, 'class': 5}]
a.loc[188,"detail"] = [{'y1': 649, 'score': 1, 'x2': 630, 'frame': 1054, 'y2': 564, 'x1': 602, 'visibility': 0.0, 'class': 5}]

For each dict, you should use pd.DataFrame.from_dict . Actually, I don't exactly that you want to print it out? or convert it into multiple dataframes.

Here is some simple solutions.

# print it 
a.applymap(lambda x:print(pd.DataFrame.from_dict({0:x[0]})))
# convert it
for i in a.index:
    tmp = pd.DataFrame.from_dict({0:a.loc[i,"detail"][0]}).T
    tmp.x2 = tmp.x2+tmp.x1
    tmp.y2 = tmp.y2 + tmp.y1
    # this function you could storge in any dict/list. Or you could storge into a list. And using pd.concat to concate them together.