Sorry, I am new in coding in Python, I would need to save a json file generated in a for loop as csv for each iteration of the loop.
I wrote a code that works fine to generate the first csv file but then it is overwritten and I did not find a solution yet. Can anyone help me? many thanks
from twarc.client2 import Twarc2
import itertools
import pandas as pd
import csv
import json
import numpy as np
# Your bearer token here
t = Twarc2(bearer_token="AAAAAAAAAAAAAAAAAAAAA....WTW")
# Get a bunch of user handles you want to check:
list_of_names = np.loadtxt("usernames.txt",dtype="str")
# Get the `data` part of every request only, as one list
def get_data(results):
return list(itertools.chain(*[result['data'] for result in results]))
user_objects = get_data(t.user_lookup(users=list_of_names, usernames=True))
for user in user_objects:
following = get_data(t.following(user['id']))
# Do something with the lists
print(f"User: {user['username']} Follows {len(following)} -2")
json_string = json.dumps(following)
df = pd.read_json(json_string)
df.to_csv('output_file.csv')
You need to add a sequence number or some other unique identifier to the filename. The clearest example would be to keep track of a counter, or use a GUID. Below I've used a counter that is initialized before your loop, and is incremented in each iteration. This will produce a list of files like output_file_1.csv, output_file_2.csv, output_file_3.csv and so on.
counter = 0
for user in user_objects:
following = get_data(t.following(user['id']))
# Do something with the lists
print(f"User: {user['username']} Follows {len(following)} -2")
json_string = json.dumps(following)
df = pd.read_json(json_string)
df.to_csv('output_file_' + str(counter) + '.csv')
counter += 1
We convert the integer to a string, and paste it inbetween the name of your file and its extension.
from twarc.client2 import Twarc2
import itertools
import pandas as pd
import csv
import json
import numpy as np
# Your bearer token here
t = Twarc2(bearer_token="AAAAAAAAAAAAAAAAAAAAA....WTW")
# Get a bunch of user handles you want to check:
list_of_names = np.loadtxt("usernames.txt",dtype="str")
# Get the `data` part of every request only, as one list
def get_data(results):
return list(itertools.chain(*[result['data'] for result in results]))
user_objects = get_data(t.user_lookup(users=list_of_names, usernames=True))
for idx, user in enumerate(user_objects):
following = get_data(t.following(user['id']))
# Do something with the lists
print(f"User: {user['username']} Follows {len(following)} -2")
json_string = json.dumps(following)
df = pd.read_json(json_string)
df.to_csv(f'output_file{str(idx)}.csv')
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()
I have a big GZ compressed JSON file where each line is a JSON object (i.e. a python dictionary).
Here is an example of the first two lines:
{"ID_CLIENTE":"o+AKj6GUgHxcFuaRk6/GSvzEWRYPXDLjtJDI79c7ccE=","ORIGEN":"oaDdZDrQCwqvi1YhNkjIJulA8C0a4mMZ7ESVlEWGwAs=","DESTINO":"OOcb8QTlctDfYOwjBI02hUJ1o3Bro/ir6IsmZRigja0=","PRECIO":0.0023907284768211919,"RESERVA":"2015-05-20","SALIDA":"2015-07-26","LLEGADA":"2015-07-27","DISTANCIA":0.48962542317352847,"EDAD":"19","sexo":"F"}{"ID_CLIENTE":"WHDhaR12zCTCVnNC/sLYmN3PPR3+f3ViaqkCt6NC3mI=","ORIGEN":"gwhY9rjoMzkD3wObU5Ito98WDN/9AN5Xd5DZDFeTgZw=","DESTINO":"OOcb8QTlctDfYOwjBI02hUJ1o3Bro/ir6IsmZRigja0=","PRECIO":0.001103046357615894,"RESERVA":"2015-04-08","SALIDA":"2015-07-24","LLEGADA":"2015-07-24","DISTANCIA":0.21382548869717155,"EDAD":"13","sexo":"M"}
So, I'm using the following code to read each line into a Pandas DataFrame:
import json
import gzip
import pandas as pd
import random
with gzip.GzipFile('data/000000000000.json.gz', 'r',) as fin:
data_lan = pd.DataFrame()
for line in fin:
data_lan = pd.DataFrame([json.loads(line.decode('utf-8'))]).append(data_lan)
But it's taking years.
Any suggestion to read the data quicker?
EDIT:
Finally what solved the problem:
import json
import gzip
import pandas as pd
with gzip.GzipFile('data/000000000000.json.gz', 'r',) as fin:
data_lan = []
for line in fin:
data_lan.append(json.loads(line.decode('utf-8')))
data = pd.DataFrame(data_lan)
I've worked on a similar problem myself, The append() is kinda slow. I generally use a list of dicts to load the json file and then create a Dataframe at once. This ways, you can have the flexibility the lists give you and only when you're sure about the Data in the list you convert it into a Dataframe. Below is an implementation of the concept:
import pandas as pd
import gzip
def get_contents_from_json(file_path)-> dict:
"""
Reads the contents of the json file into a dict
:param file_path:
:return: A dictionary of all contents in the file.
"""
try:
with gzip.open(file_path) as file:
contents = file.read()
return json.loads(contents.decode('UTF-8'))
except json.JSONDecodeError:
print('Error while reading json file')
except FileNotFoundError:
print(f'The JSON file was not found at the given path: \n{file_path}')
def main(file_path: str):
file_contents = get_contents_from_json(file_path)
if not isinstance(file_contents,list):
# I've considered you have a JSON Array in your file
# if not let me know in the comments
raise TypeError("The file doesn't have a JSON Array!!!")
all_columns = file_contents[0].keys()
data_frame = pd.DataFrame(columns=all_columns, data=file_contents)
print(f'Loaded {int(data_frame.size / len(all_columns))} Rows', 'Done!', sep='\n')
if __name__ == '__main__':
main(r'C:\Users\carrot\Desktop\dummyData.json.gz')
A pandas DataFrame fits into a contiguous block of memory which means that pandas needs to know the size of the data set when the frame is created. Since append changes the size, new memory must be allocated and the original plus new data sets are copied in. As your set grows, the copy gets bigger and bigger.
You can use from_records to avoid this problem. First, you need to know the row count and that means scanning the file. You could potentially cache that number if you do it often, but its a relatively fast operation. Now you have the size and pandas can allocate the memory efficiently.
# count rows
with gzip.GzipFile(file_to_test, 'r',) as fin:
row_count = sum(1 for _ in fin)
# build dataframe from records
with gzip.GzipFile(file_to_test, 'r',) as fin:
data_lan = pd.DataFrame.from_records(fin, nrows=row_count)
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)
I am writing record to Kinesis Firehose stream that is eventually written to a S3 file by Amazon Kinesis Firehose.
My record object looks like
ItemPurchase {
String personId,
String itemId
}
The data is written to S3 looks like:
{"personId":"p-111","itemId":"i-111"}{"personId":"p-222","itemId":"i-222"}{"personId":"p-333","itemId":"i-333"}
NO COMMA SEPERATION.
NO STARTING BRACKET as in a Json Array
[
NO ENDING BRACKET as in a Json Array
]
I want to read this data get a list of ItemPurchase objects.
List<ItemPurchase> purchases = getPurchasesFromS3(IOUtils.toString(s3ObjectContent))
What is the correct way to read this data?
It boggles my mind that Amazon Firehose dumps JSON messages to S3 in this manner, and doesn't allow you to set a delimiter or anything.
Ultimately, the trick I found to deal with the problem was to process the text file using the JSON raw_decode method
This will allow you to read a bunch of concatenated JSON records without any delimiters between them.
Python code:
import json
decoder = json.JSONDecoder()
with open('giant_kinesis_s3_text_file_with_concatenated_json_blobs.txt', 'r') as content_file:
content = content_file.read()
content_length = len(content)
decode_index = 0
while decode_index < content_length:
try:
obj, decode_index = decoder.raw_decode(content, decode_index)
print("File index:", decode_index)
print(obj)
except JSONDecodeError as e:
print("JSONDecodeError:", e)
# Scan forward and keep trying to decode
decode_index += 1
I also had the same problem, here is how I solved.
replace "}{" with "}\n{"
line split by "\n".
input_json_rdd.map(lambda x : re.sub("}{", "}\n{", x, flags=re.UNICODE))
.flatMap(lambda line: line.split("\n"))
A nested json object has several "}"s, so split line by "}" doesn't solve the problem.
I've had the same issue.
It would have been better if AWS allowed us to set a delimiter but we can do it on our own.
In my use case, I've been listening on a stream of tweets, and once receiving a new tweet I immediately put it to Firehose.
This, of course, resulted in a 1-line file which could not be parsed.
So, to solve this, I have concatenated the tweet's JSON with a \n.
This, in turn, let me use some packages that can output lines when reading stream contents, and parse the file easily.
Hope this helps you.
I think the best ways to tackle this is to first create a properly formatted json file containing well separated json objects within them. In my case I added ',' to the events which was pushed into the firehose. Then After a file is saved in s3, all the files will contain json object separated by some delimitter(comma- in our case). Another thing that must be added are '[' and ']' at the beginning and end of the file. Then you have a proper json file containing multiple json objects. Parsing them will be possible now.
If the input source for the firehose is an Analytics application, this concatenated JSON without a delimiter is a known issue as cited here. You should have a lambda function as here that outputs JSON objects in multiple lines.
I used a transformation Lambda to add a line break at the end of every record
def lambda_handler(event, context):
output = []
for record in event['records']:
# Decode from base64 (Firehose records are base64 encoded)
payload = base64.b64decode(record['data'])
# Read json as utf-8
json_string = payload.decode("utf-8")
# Add a line break
output_json_with_line_break = json_string + "\n"
# Encode the data
encoded_bytes = base64.b64encode(bytearray(output_json_with_line_break, 'utf-8'))
encoded_string = str(encoded_bytes, 'utf-8')
# Create a deep copy of the record and append to output with transformed data
output_record = copy.deepcopy(record)
output_record['data'] = encoded_string
output_record['result'] = 'Ok'
output.append(output_record)
print('Successfully processed {} records.'.format(len(event['records'])))
return {'records': output}
Use this simple Python code.
input_str = '''{"personId":"p-111","itemId":"i-111"}{"personId":"p-222","itemId":"i-222"}{"personId":"p-333","itemId":"i-333"}'''
data_str = "[{}]".format(input_str.replace("}{","},{"))
data_json = json.loads(data_str)
And then (if you want) convert to Pandas.
import pandas as pd
df = pd.DataFrame().from_records(data_json)
print(df)
And this is result
itemId personId
0 i-111 p-111
1 i-222 p-222
2 i-333 p-333
If there's a way to change the way data is written, please separate all the records by a line. That way you can read the data simply, line by line. If not, then simply build a scanner object which takes "}" as a delimiter and use the scanner to read. That would do the job.
You can find the each valid JSON by counting the brackets. Assuming the file starts with a { this python snippet should work:
import json
def read_block(stream):
open_brackets = 0
block = ''
while True:
c = stream.read(1)
if not c:
break
if c == '{':
open_brackets += 1
elif c == '}':
open_brackets -= 1
block += c
if open_brackets == 0:
yield block
block = ''
if __name__ == "__main__":
c = 0
with open('firehose_json_blob', 'r') as f:
for block in read_block(f):
record = json.loads(block)
print(record)
This problem can be solved with a JSON parser that consumes objects one at a time from a stream. The raw_decode method of the JSONDecoder exposes just such a parser, but I've written a library that makes it straightforward to do this with a one-liner.
from firehose_sipper import sip
for entry in sip(bucket=..., key=...):
do_something_with(entry)
I've added some more details in this blog post
In Spark, we had the same problem. We're using the following:
from pyspark.sql.functions import *
#udf
def concatenated_json_to_array(text):
final = "["
separator = ""
for part in text.split("}{"):
final += separator + part
separator = "}{" if re.search(r':\s*"([^"]|(\\"))*$', final) else "},{"
return final + "]"
def read_concatenated_json(path, schema):
return (spark.read
.option("lineSep", None)
.text(path)
.withColumn("value", concatenated_json_to_array("value"))
.withColumn("value", from_json("value", schema))
.withColumn("value", explode("value"))
.select("value.*"))
It works as follows:
Read the data as one string per file (no delimiters!)
Use a UDF to introduce the JSON array and split the JSON objects by introducing a comma. Note: be careful not to break any strings with }{ in them!
Parse the JSON with a schema into DataFrame fields.
Explode the array into separate rows
Expand the value object into column.
Use it like this:
from pyspark.sql.types import *
schema = ArrayType(
StructType([
StructField("type", StringType(), True),
StructField("value", StructType([
StructField("id", IntegerType(), True),
StructField("joke", StringType(), True),
StructField("categories", ArrayType(StringType()), True)
]), True)
])
)
path = '/mnt/my_bucket_name/messages/*/*/*/*/'
df = read_concatenated_json(path, schema)
I've written more details and considerations here: Parsing JSON data from S3 (Kinesis) with Spark. Do not just split by }{, as it can mess up your string data! For example: { "line": "a\"r}{t" }.
You can use below script.
If streamed data size is not over buffer size that you set, each file of s3 have one pair of brackets([]) and comma.
import base64
print('Loading function')
def lambda_handler(event, context):
output = []
for record in event['records']:
print(record['recordId'])
payload = base64.b64decode(record['data']).decode('utf-8')+',\n'
# Do custom processing on the payload here
output_record = {
'recordId': record['recordId'],
'result': 'Ok',
'data': base64.b64encode(payload.encode('utf-8'))
}
output.append(output_record)
last = len(event['records'])-1
print('Successfully processed {} records.'.format(len(event['records'])))
start = '['+base64.b64decode(output[0]['data']).decode('utf-8')
end = base64.b64decode(output[last]['data']).decode('utf-8')+']'
output[0]['data'] = base64.b64encode(start.encode('utf-8'))
output[last]['data'] = base64.b64encode(end.encode('utf-8'))
return {'records': output}
Using JavaScript Regex.
JSON.parse(`[${item.replace(/}\s*{/g, '},{')}]`);