Parsing bulk conversion from JSON to CSV - json

I am using the following code in Python 3 to convert ~30,000 json files to a csv.
with open('out.csv', 'w') as f:
for fname in glob("*.json"): # Reads all json from the current directory
with open(fname) as j:
f.write(str(json.load(j)))
f.write('\n')
The json files are timestamps and values, for example {"1501005600":956170,"1501048800":970046,...
The output currently is
.
How can I put each in their own respective cells so the output is ?
I have tried many approaches with csv.writer but I cannot figure this out.
UPDATE
with open('out.csv', 'w') as f:
for fname in glob("*.json"):
with open(fname) as j:
values = json.load(j)
for k, v in values.items():
f.write("{},{},".format(str(k), str(v)))
Parsing is correct but each .json file is on one row now.

A friend helped me get to the bottom of this, hope this may help others.
with open('[insert].csv', 'w') as f:
for fname in glob("*.json"):
with open(fname) as j:
values = json.load(j)
for k, v in values.items():
f.write("{},{},".format(str(k), str(v)))
f.write('\n')

Related

How to convert xml to Json from one directory to other directory

I have a scenario like in one folder having 100 xmls so need to convert in to json with the same names of json instead of xml i have tried many ways but all xmls are converting into one json but i need separate json files
by using this all 100 xmls files are converting into one json file but i need 100 seprate json files, can anyone please suggest best approach
for path, dirs, files in os.walk(r"C:\exml\FND_GLS".format(type) ):
for f in files:
clinical = os.path.join(path, f)
print(clinical)
tree = ET.parse(clinical)
root = tree.getroot()
xmlstr = ET.tostring(root, encoding='utf-8', method='xml')
data_dict = dict(xmltodict.parse(xmlstr))
def write_json(target_path, target_file, data):
if not os.path.exists(target_path):
try:
os.makedirs(target_path)
except Exception as e:
print(e)
raise
with open(os.path.join(target_path, target_file), 'w') as f:
data = json.dump(data_dict,f, sort_keys=False, indent=4)
write_json('C:\ejson\FND_GLS_Json', 'my_json.json', 'data')

AWS Athena export array of structs to JSON

I've got an Athena table where some fields have a fairly complex nested format. The backing records in S3 are JSON. Along these lines (but we have several more levels of nesting):
CREATE EXTERNAL TABLE IF NOT EXISTS test (
timestamp double,
stats array<struct<time:double, mean:double, var:double>>,
dets array<struct<coords: array<double>, header:struct<frame:int,
seq:int, name:string>>>,
pos struct<x:double, y:double, theta:double>
)
ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe'
WITH SERDEPROPERTIES ('ignore.malformed.json'='true')
LOCATION 's3://test-bucket/test-folder/'
Now we need to be able to query the data and import the results into Python for analysis. Because of security restrictions I can't connect directly to Athena; I need to be able to give someone the query and then they will give me the CSV results.
If we just do a straight select * we get back the struct/array columns in a format that isn't quite JSON.
Here's a sample input file entry:
{"timestamp":1520640777.666096,"stats":[{"time":15,"mean":45.23,"var":0.31},{"time":19,"mean":17.315,"var":2.612}],"dets":[{"coords":[2.4,1.7,0.3], "header":{"frame":1,"seq":1,"name":"hello"}}],"pos": {"x":5,"y":1.4,"theta":0.04}}
And example output:
select * from test
"timestamp","stats","dets","pos"
"1.520640777666096E9","[{time=15.0, mean=45.23, var=0.31}, {time=19.0, mean=17.315, var=2.612}]","[{coords=[2.4, 1.7, 0.3], header={frame=1, seq=1, name=hello}}]","{x=5.0, y=1.4, theta=0.04}"
I was hoping to get those nested fields exported in a more convenient format - getting them in JSON would be great.
Unfortunately it seems that cast to JSON only works for maps, not structs, because it just flattens everything into arrays:
SELECT timestamp, cast(stats as JSON) as stats, cast(dets as JSON) as dets, cast(pos as JSON) as pos FROM "sampledb"."test"
"timestamp","stats","dets","pos"
"1.520640777666096E9","[[15.0,45.23,0.31],[19.0,17.315,2.612]]","[[[2.4,1.7,0.3],[1,1,""hello""]]]","[5.0,1.4,0.04]"
Is there a good way to convert to JSON (or another easy-to-import format) or should I just go ahead and do a custom parsing function?
I have skimmed through all the documentation and unfortunately there seems to be no way to do this as of now. The only possible workaround is
converting a struct to a json when querying athena
SELECT
my_field,
my_field.a,
my_field.b,
my_field.c.d,
my_field.c.e
FROM
my_table
Or I would convert the data to json using post processing. Below script shows how
#!/usr/bin/env python
import io
import re
pattern1 = re.compile(r'(?<={)([a-z]+)=', re.I)
pattern2 = re.compile(r':([a-z][^,{}. [\]]+)', re.I)
pattern3 = re.compile(r'\\"', re.I)
with io.open("test.csv") as f:
headers = list(map(lambda f: f.strip(), f.readline().split(",")))
for line in f.readlines():
orig_line = line
data = []
for i, l in enumerate(line.split('","')):
data.append(headers[i] + ":" + re.sub('^"|"$', "", l))
line = "{" + ','.join(data) + "}"
line = pattern1.sub(r'"\1":', line)
line = pattern2.sub(r':"\1"', line)
print(line)
The output on your input data is
{"timestamp":1.520640777666096E9,"stats":[{"time":15.0, "mean":45.23, "var":0.31}, {"time":19.0, "mean":17.315, "var":2.612}],"dets":[{"coords":[2.4, 1.7, 0.3], "header":{"frame":1, "seq":1, "name":"hello"}}],"pos":{"x":5.0, "y":1.4, "theta":0.04}
}
Which is a valid JSON
The python code from #tarun almost got me there, but I had to modify it in several ways due to my data. In particular, I have:
json structures saved in Athena as strings
Strings that contain multiple words, and therefore need to be in between double quotes. Some of them contain "[]" and "{}" symbols.
Here is the code that worked for me, hopefully will be useful for others:
#!/usr/bin/env python
import io
import re, sys
pattern1 = re.compile(r'(?<={)([a-z]+)=', re.I)
pattern2 = re.compile(r':([a-z][^,{}. [\]]+)', re.I)
pattern3 = re.compile(r'\\"', re.I)
with io.open(sys.argv[1]) as f:
headers = list(map(lambda f: f.strip(), f.readline().split(",")))
print(headers)
for line in f.readlines():
orig_line = line
#save the double quote cases, which mean there is a string with quotes inside
line = re.sub('""', "#", orig_line)
data = []
for i, l in enumerate(line.split('","')):
item = re.sub('^"|"$', "", l.rstrip())
if (item[0] == "{" and item[-1] == "}") or (item[0] == "[" and item[-1] == "]"):
data.append(headers[i] + ":" + item)
else: #we have a string
data.append(headers[i] + ": \"" + item + "\"")
line = "{" + ','.join(data) + "}"
line = pattern1.sub(r'"\1":', line)
line = pattern2.sub(r':"\1"', line)
#restate the double quotes to single ones, once inside the json
line = re.sub("#", '"', line)
print(line)
This method is not by modifying the Query.
Its by Post Processing For Javascript/Nodejs we can use the npm package athena-struct-parser.
Detailed Answer with Example
https://stackoverflow.com/a/67899845/6662952
Reference - https://www.npmjs.com/package/athena-struct-parser
I used a simple approach to get around the struct -> json Athena limitation. I created a second table where the json columns were saved as raw strings. Using presto json and array functions I was able to query the data and return the valid json string to my program:
--Array transform functions too
select
json_extract_scalar(dd, '$.timestamp') as timestamp,
transform(cast(json_extract(json_parse(dd), '$.stats') as ARRAY<JSON>), x -> json_extract_scalar(x, '$.time')) as arr_stats_time,
transform(cast(json_extract(json_parse(dd), '$.stats') as ARRAY<JSON>), x -> json_extract_scalar(x, '$.mean')) as arr_stats_mean,
transform(cast(json_extract(json_parse(dd), '$.stats') as ARRAY<JSON>), x -> json_extract_scalar(x, '$.var')) as arr_stats_var
from
(select '{"timestamp":1520640777.666096,"stats":[{"time":15,"mean":45.23,"var":0.31},{"time":19,"mean":17.315,"var":2.612}],"dets":[{"coords":[2.4,1.7,0.3], "header":{"frame":1,"seq":1,"name":"hello"}}],"pos": {"x":5,"y":1.4,"theta":0.04}}' as dd);
I know the query will take longer to execute but there are ways to optimize.
I worked around this by creating a second table using the same S3 location, but changed the field's data type to string. The resulting CSV then had the string that Athena pulled from the object in the JSON file and I was able to parse the result.
I also had to adjust the #tarun code, because I had more complex data and nested structures. Here is the solution I've got, I hope it helps:
import re
import json
import numpy as np
pattern1 = re.compile(r'(?<=[{,\[])\s*([^{}\[\],"=]+)=')
pattern2 = re.compile(r':([^{}\[\],"]+|()(?![{\[]))')
pattern3 = re.compile(r'"null"')
def convert_metadata_to_json(value):
if type(value) is str:
value = pattern1.sub('"\\1":', value)
value = pattern2.sub(': "\\1"', value)
value = pattern3.sub('null', value)
elif np.isnan(value):
return None
return json.loads(value)
df = pd.read_csv('test.csv')
df['metadata_json'] = df.metadata.apply(convert_metadata_to_json)

Python Spark- How to output empty DataFrame to csv file (Only output header)?

I want to output empty dataframe to csv file. I use these codes:
df.repartition(1).write.csv(path, sep='\t', header=True)
But due to there is no data in dataframe, spark won't output header to csv file.
Then I modify the codes to:
if df.count() == 0:
empty_data = [f.name for f in df.schema.fields]
df = ss.createDataFrame([empty_data], df.schema)
df.repartition(1).write.csv(path, sep='\t')
else:
df.repartition(1).write.csv(path, sep='\t', header=True)
It works, but I want to ask whether there are a better way without count function.
df.count() == 0 will make your driver program retrieve the count of all your dataframe partitions across the executors.
In your case I would use df.take(1).isEmpty (Spark >= 2.1). Still slow, but preferable to a raw count().
Only header:
cols = '\t'.join(df.columns)
with open('./cols.csv', 'w') as f:
f.write(cols)

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.

Converting JSON files to .csv

I've found some data that someone is downloading into a JSON file (I think! - I'm a newb!). The file contains data on nearly 600 football players.
Here you can find the file
In the past, I have downloaded the json file and then used this code:
import csv
import json
json_data = open("file.json")
data = json.load(json_data)
f = csv.writer(open("fix_hists.csv","wb+"))
arr = []
for i in data:
fh = data[i]["fixture_history"]
array = fh["all"]
for j in array:
try:
j.insert(0,str(data[i]["first_name"]))
except:
j.insert(0,'error')
try:
j.insert(1,data[i]["web_name"])
except:
j.insert(1,'error')
try:
f.writerow(j)
except:
f.writerow(['error','error'])
json_data.close()
Sadly, when I do this now in command prompt, i get the following error:
Traceback (most recent call last):
File"fix_hist.py", line 12 (module)
fh = data[i]["fixture_history"]
TypeError: list indices must be integers, not str
Can this be fixed or is there another way I can grab some of the data and convert it to .csv? Specifically the 'Fixture History'? and then 'First'Name', 'type_name' etc.
Thanks in advance for any help :)
Try this tool: http://www.convertcsv.com/json-to-csv.htm
You will need to configure a few things, but should be easy enough.