How to convert this json file to pandas dataframe - json

The format in the file looks like this
{ 'match' : 'a', 'score' : '2'},{......}
I've tried pd.DataFrame and I've also tried reading it by line but it gives me everything in one cell
I'm new to python
Thanks in advance
Expected result is a pandas dataframe

Try use json_normalize() function
Example:
from pandas.io.json import json_normalize
values = [{'match': 'a', 'score': '2'}, {'match': 'b', 'score': '3'}, {'match': 'c', 'score': '4'}]
df = json_normalize(values)
print(df)
Output:

If one line of your file corresponds to one JSON object, you can do the following:
# import library for working with JSON and pandas
import json
import pandas as pd
# make an empty list
data = []
# open your file and add every row as a dict to the list with data
with open("/path/to/your/file", "r") as file:
for line in file:
data.append(json.loads(line))
# make a pandas data frame
df = pd.DataFrame(data)
If there is more than only one JSON object on one row of your file, then you should find those JSON objects, for example here are two possible options. The solution with the second option would look like this:
# import all you will need
import pandas as pd
import json
from json import JSONDecoder
# define function
def extract_json_objects(text, decoder=JSONDecoder()):
pos = 0
while True:
match = text.find('{', pos)
if match == -1:
break
try:
result, index = decoder.raw_decode(text[match:])
yield result
pos = match + index
except ValueError:
pos = match + 1
# make an empty list
data = []
# open your file and add every JSON object as a dict to the list with data
with open("/path/to/your/file", "r") as file:
for line in file:
for item in extract_json_objects(line):
data.append(item)
# make a pandas data frame
df = pd.DataFrame(data)

Related

Pandas parallel URL downloads with pd.read_html

I know I can download a csv file from a web page by doing:
import pandas as pd
import numpy as np
from io import StringIO
URL = "http://www.something.com"
data = pd.read_html(URL)[0].to_csv(index=False, header=True)
file = pd.read_csv(StringIO(data), sep=',')
Now I would like to do the above for more URLs at the same time, like when you open different tabs in your browser. In other words, a way to parallelize this when you have different URLs, instead of looping through or doing it one at a time. So, I thought of having a series of URLs inside a dataframe, and then create a new column which contains the strings 'data', one for each URL.
list_URL = ["http://www.something.com", "http://www.something2.com",
"http://www.something3.com"]
df = pd.DataFrame(list_URL, columns =['URL'])
df['data'] = pd.read_html(df['URL'])[0].to_csv(index=False, header=True)
But it gives me error: cannot parse from 'Series'
Is there a better syntax, or does this mean I cannot do this in parallel for more than one URL?
You could try like this:
import pandas as pd
URLS = [
"https://en.wikipedia.org/wiki/Periodic_table#Presentation_forms",
"https://en.wikipedia.org/wiki/Planet#Planetary_attributes",
]
df = pd.DataFrame(URLS, columns=["URL"])
df["data"] = df["URL"].map(
lambda x: pd.read_html(x)[0].to_csv(index=False, header=True)
)
print(df)
# Output
URL data
0 https://en.wikipedia.org/wiki/Periodic_t... 0\r\nPart of a series on the\r\nPeriodic...
1 https://en.wikipedia.org/wiki/Planet#Pla... 0\r\n"The eight known planets of the Sol...

Pandas ExcelWriter removing valid NaN values when they are needed in output spreadsheet

I am using Pandas to load a json file and output it to Excel via the ExcelWriter. "NaN" is a valid value in the json and is getting stripped in the spreadsheet. How can I store the NaN value.
Here's the json input file (simple_json_test.json)
{"action_time":"2020-04-23T07:39:51.918Z","triggered_value":"NaN"}
{"action_time":"2020-04-23T07:39:51.918Z","triggered_value":"2"}
{"action_time":"2020-04-23T07:39:51.918Z","triggered_value":"1"}
{"action_time":"2020-04-23T07:39:51.918Z","triggered_value":"NaN"}
Here's the python code:
import pandas as pd
from datetime import datetime
with open('simple_json_test.json', 'r') as f:
data = f.readlines()
data = map(lambda x: x.rstrip(), data)
data_json_str = "[" + ','.join(data) + "]"
df = pd.read_json(data_json_str)
# Write dataframe to excel
df['action_time'] = df['action_time'].dt.tz_localize(None)
# Write the dataframe to excel
writer = pd.ExcelWriter('jsonNaNExcelTest.xlsx', engine='xlsxwriter',datetime_format='yyy-mm-dd hh:mm:ss.000')
df.to_excel(writer, header=True, sheet_name='Pandas_Test',index=False)
# Widen the columns
worksheet = writer.sheets['Pandas_Test']
worksheet.set_column('A:B', 25)
writer.save()
Here's the output excel file:
Once that basic question is answer, i want to be able to specify which columns "NaN' is a valid value so save it to excel.
The default action for to_excel() is to convert NaN to the empty string ''. See the Pandas docs for to_excel() and the na_rep parameter.
You can specify an alternative like this:
df.to_excel(writer, header=True, sheet_name='Pandas_Test',
index=False, na_rep='NaN')

Export JSON to CSV using Python

I wrote a code to extract some information from a website. the output is in JSON and I want to export it to CSV. So, I tried to convert it to a pandas dataframe and then export it to CSV in pandas. I can print the results but still, it doesn't convert the file to a pandas dataframe. Do you know what the problem with my code is?
# -*- coding: utf-8 -*-
# To create http request/session
import requests
import re, urllib
import pandas as pd
from BeautifulSoup import BeautifulSoup
url = "https://www.indeed.com/jobs?
q=construction%20manager&l=Houston&start=10"
# create session
s = requests.session()
html = s.get(url).text
# exctract job IDs
job_ids = ','.join(re.findall(r"jobKeysWithInfo\['(.+?)'\]", html))
ajax_url = 'https://www.indeed.com/rpc/jobdescs?jks=' +
urllib.quote(job_ids)
# do Ajax request and convert the response to json
ajax_content = s.get(ajax_url).json()
print(ajax_content)
#Convert to pandas dataframe
df = pd.read_json(ajax_content)
#Export to CSV
df.to_csv("c:\\users\\Name\desktop\\newcsv.csv")
The error message is:
Traceback (most recent call last):
File "C:\Users\Mehrdad\Desktop\Indeed 06.py", line 21, in
df = pd.read_json(ajax_content)
File "c:\python27\lib\site-packages\pandas\io\json\json.py", line 408, in read_json
path_or_buf, encoding=encoding, compression=compression,
File "c:\python27\lib\site-packages\pandas\io\common.py", line 218, in get_filepath_or_buffer
raise ValueError(msg.format(_type=type(filepath_or_buffer)))
ValueError: Invalid file path or buffer object type:
The problem was that nothing was going into the dataframe when you called read_json() because it was a nested JSON dict:
import requests
import re, urllib
import pandas as pd
from pandas.io.json import json_normalize
url = "https://www.indeed.com/jobs?q=construction%20manager&l=Houston&start=10"
s = requests.session()
html = s.get(url).text
job_ids = ','.join(re.findall(r"jobKeysWithInfo\['(.+?)'\]", html))
ajax_url = 'https://www.indeed.com/rpc/jobdescs?jks=' + urllib.quote(job_ids)
ajax_content= s.get(ajax_url).json()
df = json_normalize(ajax_content).transpose()
df.to_csv('your_output_file.csv')
Note that I called json_normalize() to collapse the nested columns from the JSON. I also called transpose() so that the rows were labelled with the job ID rather than columns. This will give you a dataframe that looks like this:
0079ccae458b4dcf <p><b>Company Environment: </b></p><p>Planet F...
0c1ab61fe31a5c62 <p><b>Commercial Construction Project Manager<...
0feac44386ddcf99 <div><div>Trendmaker Homes is currently seekin...
...
It's not really clear what your expected output is, though ... what are you expecting the DataFrame/CSV file to look like?. If you actually were looking for just a single row/Series with the job ID's as column labels, just remove the call to transpose()

Setting column on empty dataframe

I'm reading json arrays from a text file and then create an empty dataframe. I want to add a new column 'id' to the empty dataframe. 'id' comes from the json arrays in the text file.
Error message reads "Cannot set a frame with no defined index and a value that canot be converted to a series". I tried to overcome this error by defining dataframe size upfront which did not help. Any ideas?
import json
import pandas as pd
path = 'my/path'
mydata = []
myfile = open(path, "r")
for line in myfile:
try:
myline = json.loads(line)
mydata.append(myline)
except:
continue
mydf = pd.DataFrame()
mydf['id'] = map(lambda myline: myline['id'], mydata)
I think better is use:
for line in myfile:
try:
#extract only id to list
myline = json.loads(line)['id']
mydata.append(myline)
except:
continue
print (mydata)
[10, 5]
#create DataFrame by constructor
mydf = pd.DataFrame({'id':mydata})
print (mydf)
id
0 10
1 5

How do I grab info from this json file?

I'm trying to grab some numbers from this json file, but I don't how to do it correctly. This is the json file I am trying to gather information from:
http://stats.nba.com/stats/leaguedashteamstats?Conference=&DateFrom=&DateTo=&Division=&GameScope=&GameSegment=&LastNGames=0&LeagueID=00&Location=&MeasureType=Base&Month=0&OpponentTeamID=0&Outcome=&PORound=0&PaceAdjust=N&PerMode=PerGame&Period=0&PlayerExperience=&PlayerPosition=&PlusMinus=N&Rank=N&Season=2016-17&SeasonSegment=&SeasonType=Regular+Season&ShotClockRange=&StarterBench=&TeamID=0&VsConference=&VsDivision=
I've been trying to get this code to work, but I can't figure it out:
import json
from pprint import pprint
with open('data.json') as data_file:
data = json.load(data_file)
data["rowSet"] ["1610612737"] ["Atlanta Hawks"]
I'm trying to get the statistics from each team.
The following Python script should do it.
#!/usr/bin/env python
import json
with open('leaguedashteamstats.json') as data_file:
data = json.load(data_file)
# extract headers names
headers = data['resultSets'][0]['headers']
# extract raw json rows
raw_rows = data['resultSets'][0]['rowSet']
team_stats = []
for row in raw_rows:
print row[1] # prints team name
# mixes header names and values and prints them out
for (header, value) in zip(headers, row):
print header, value
print '\n'
Both data and code can be seen here:
https://gist.github.com/cevaris/24d0b7d97677667aedb14059a6959da1#file-1-team-stats-output
Disclaimer: this code doesn't contain any validation, but it should lead you in the right direction:
import json
with open('data.json') as data_file:
data = json.load(data_file)
for rs in data.get('resultSets'):
for r_ in [r for r in rs.get('rowSet') if r[1] == 'Atlanta Hawks']:
print(r_)
You basically need to determine specific keys that you are going to loop through, or obtain.
This should hopefully get you to where you need to be.