无法从数据框熊猫中提取列

Question

I'm reading the json file and extracting the required columns into the csv file .Please find the below code and let me know if am wrong

df=pd.read_json(json_file)
df=df['Person']
data1=pd.DataFrame(df,columns=['cols1','cols2','cols3','title'])

print data1

df.to_csv("ptr1.csv",index = False)

but i'm getting the error empty dataframe output .

Answer 1

It seems you need:

import json
from pandas.io.json import json_normalize

with open('file.json') as data_file:    
    data = json.load(data_file) 

df = json_normalize(data, 'Person')

Sample:

data = {"Person": [{ "cols1" : 1, "cols2" : "value2", "cols3" : "value1", "title" : "ptr" }]}

df = json_normalize(data, 'Person')
print (df)
   cols1   cols2   cols3 title
0      1  value2  value1   ptr

Answer 2

Still i'm getting the empty dataframe .Please find the below code

json_file = open("file.json")

df=pd.read_json(json_file)

data=json_normalize(json_file, 'Person')
print data

Getting output : Empty DataFrame Columns: [] Index: []