Develop Reference

How to check each key separately from a list in a loop without creating multiple loops. Which may have a KeyError etc

I wrote a code that takes 9 keys from API.
The authors, isbn_one, isbn_two, thumbinail, page_count fields may not always be retrievable, and if any of them are missing, I would like it to be None. Unfortunately, if, or even nested, doesn't work. Because that leads to a lot of loops. I also tried try and except KeyError etc. because each key has a different error and it is not known which to assign none to. Here is an example of logic when a photo is missing:
th = result['volumeInfo'].get('imageLinks')
if th is not None:
book_exists_thumbinail = {
'thumbinail': result['volumeInfo']['imageLinks']['thumbnail']
}
dnew = {**book_data, **book_exists_thumbinail}
book_import.append(dnew)
else:
book_exists_thumbinail_n = {
'thumbinail': None
}
dnew_none = {**book_data, **book_exists_thumbinail_n}
book_import.append(dnew_none)
When I use logic, you know when one condition is met, e.g. for thumbinail, the rest is not even checked.
When I use try and except, it's similar. There's also an ISBN in the keys, but there's a list in the dictionary over there, and I need to use something like this:
isbn_zer = result['volumeInfo']['industryIdentifiers']
dic = collections.defaultdict(list)
for d in isbn_zer:
for k, v in d.items():
dic[k].append(v)
Output data: [{'type': 'ISBN_10', 'identifier': '8320717507'}, {'type': 'ISBN_13', 'identifier': '9788320717501'}]
I don't know what to use anymore to check each key separately and in the case of its absence or lack of one ISBN (identifier) assign the value None. I have already tried many ideas.
The rest of the code:
book_import = []
if request.method == 'POST':
filter_ch = BookFilterForm(request.POST)
if filter_ch.is_valid():
cd = filter_ch.cleaned_data
filter_choice = cd['choose_v']
filter_search = cd['search']
search_url = "https://www.googleapis.com/books/v1/volumes?"
params = {
'q': '{}{}'.format(filter_choice, filter_search),
'key': settings.BOOK_DATA_API_KEY,
'maxResults': 2,
'printType': 'books'
}
r = requests.get(search_url, params=params)
results = r.json()['items']
for result in results:
book_data = {
'title': result['volumeInfo']['title'],
'authors': result['volumeInfo']['authors'][0],
'publish_date': result['volumeInfo']['publishedDate'],
'isbn_one': result['volumeInfo']['industryIdentifiers'][0]['identifier'],
'isbn_two': result['volumeInfo']['industryIdentifiers'][1]['identifier'],
'page_count': result['volumeInfo']['pageCount'],
'thumbnail': result['volumeInfo']['imageLinks']['thumbnail'],
'country': result['saleInfo']['country']
}
book_import.append(book_data)
else:
filter_ch = BookFilterForm()
return render(request, "BookApp/book_import.html", {'book_import': book_import,
'filter_ch': filter_ch})```

rename duplicate key in json file python

I have json file which has duplicate keys.
Example
{
"data":"abc",
"data":"xyz"
}
I want to make this as
{
"data1":"abc",
"data2":"xyz"
}
I tried using object_pairs_hook with json_loads, but it is not working. Could anyone one help me with Python solution for above problem

You can pass the load method a keyword parameter to handle pairing, there you can check for duplicates like this:
raw_text_data = """{
"data":"abc",
"data":"xyz",
"data":"xyz22"
}"""
def manage_duplicates(pairs):
d = {}
k_counter = Counter(defaultdict(int))
for k, v in pairs:
d[k+str(k_counter[k])] = v
k_counter[k] += 1
return d
print(json.loads(raw_text_data, object_pairs_hook=manage_duplicates))
I used Counter to count each key, if it already exists, I'm saving the key as k+str(k_counter[k) - so it will be added with a trailing number.
P.S
If you have control on the input, I would highly recommend to change your json structure to:
{"data": ["abc", "xyz"]}
The rfc 4627 for application/json media type recommends unique keys but it doesn't forbid them explicitly:
The names within an object SHOULD be unique.

A quick and dirty solution using re.
import re
s = '{ "data":"abc", "data":"xyz", "test":"one", "test":"two", "no":"numbering" }'
def find_dupes(s):
keys = re.findall(r'"(\w+)":', s)
return list(set(filter(lambda w: keys.count(w) > 1, keys)))
for key in find_dupes(s):
for i in range(1, len(re.findall(r'"{}":'.format(key), s)) + 1):
s = re.sub(r'"{}":'.format(key), r'"{}{}":'.format(key, i), s, count=1)
print(s)
Prints this string:
{
"data1":"abc",
"data2":"xyz",
"test1":"one",
"test2":"two",
"no":"numbering"
}

Python - Parsing JSON Data Set

I am trying to parse a JSON data set that looks something like this:
{"data":[
{
"Rest":0,
"Status":"The campaign is moved to the archive",
"IsActive":"No",
"StatusArchive":"Yes",
"Login":"some_login",
"ContextStrategyName":"Default",
"CampaignID":1111111,
"StatusShow":"No",
"StartDate":"2013-01-20",
"Sum":0,
"StatusModerate":"Yes",
"Clicks":0,
"Shows":0,
"ManagerName":"XYZ",
"StatusActivating":"Yes",
"StrategyName":"HighestPosition",
"SumAvailableForTransfer":0,
"AgencyName":null,
"Name":"Campaign_01"
},
{
"Rest":82.6200000000008,
"Status":"Impressions will begin tomorrow at 10:00",
"IsActive":"Yes",
"StatusArchive":"No",
"Login":"some_login",
"ContextStrategyName":"Default",
"CampaignID":2222222,
"StatusShow":"Yes",
"StartDate":"2013-01-28",
"Sum":15998,"StatusModerate":"Yes",
"Clicks":7571,
"Shows":5535646,
"ManagerName":"XYZ",
"StatusActivating":"Yes",
"StrategyName":"HighestPosition",
"SumAvailableForTransfer":0,
"AgencyName":null,
"Name":"Campaign_02"
}
]
}
Lets assume that there can be many of these data sets.
I would like to iterate through each one of them and grab the "Name" and the "Campaign ID" parameter.
So far my code looks something like this:
decoded_response = response.read().decode("UTF-8")
data = json.loads(decoded.response)
for item in data[0]:
for x in data[0][item] ...
-> need a get name procedure
-> need a get campaign_id procedure
Probably quite straight forward! I am not good with lists/dictionaries :(

Access dictionaries with d[dict_key] or d.get(dict_key, default) (to provide default value):
jsonResponse=json.loads(decoded_response)
jsonData = jsonResponse["data"]
for item in jsonData:
name = item.get("Name")
campaignID = item.get("CampaignID")
I suggest you read something about dictionaries.

Accessing json type data without knowing layout of data?

I have a file with JSON data I am loading using json.load.
Suppose I want to put a variable in the json data, which references another data field. How can I process this reference in python?
eg:
{
"dictionary" : {
"list_1" : [
"item_1"
],
"list_2" : [
"$dictionary.list_1"
]
}
}
when I come across $, I then want list_2 to grab the data from: dictionary.list_1
and extend list_2, as if I had written in my python code:
jsonData["dictionary"]["list_2"].extend(jsonData["dictionary"]["list_1"])

As far as I know, there is nothing in the JSON standard for doing references. My first suggestion would be to use YAML which does have references in the form of Node Anchors. Python has a good implementation of YAML which supports those.
That being said, if you're set on using JSON, you'll have to roll your own implementation.
One possible example(though this doesn't extend the current array by the referenced array because that's ambiguous in the case of dicts, it replaces the reference by the value it refers to) is below. Note that it doesn't handle malformed references you'll have to add the error-checking yourself or guarantee that there aren't malformed references. If you want to change it to extend instead of replacing, you can, but you know your use-case better than I so you'll be able to specify it that way. This is meant to give you a starting point.
def resolve_references(structure, sub_structure=None):
if sub_structure is None:
return resolve_references(structure, structure)
if isinstance(sub_structure, list):
tmp = []
for item in sub_structure:
tmp.append(resolve_references(structure, item))
return tmp
if isinstance(sub_structure, dict):
tmp = {}
for key,value in sub_structure.items():
tmp[key] = resolve_references(structure, value)
return tmp
if isinstance(sub_structure, str) or isinstance(sub_structure, unicode):
if sub_structure[0] != "$":
return sub_structure
keys = sub_structure[1:].split(".")
def get_value(obj, key):
if isinstance(obj, dict):
return obj[key]
if isinstance(obj, list):
return obj[int(key)]
return value
value = get_value(structure, keys[0])
for key in keys[1:]:
value = get_value(value, key)
return value
return sub_structure
Example usage:
>>> import json
>>> json_str = """
... {
... "dictionary" : {
... "list_1" : [
... "item_1"
... ],
...
... "list_2" : "$dictionary.list_1"
... }
... }
... """
>>> obj = json.loads(json_str)
>>> resolve_references(obj)
{u'dictionary': {u'list_2': [u'item_1'], u'list_1': [u'item_1']}}

Xpath like query for nested python dictionaries

Is there a way to define a XPath type query for nested python dictionaries.
Something like this:
foo = {
'spam':'eggs',
'morefoo': {
'bar':'soap',
'morebar': {'bacon' : 'foobar'}
}
}
print( foo.select("/morefoo/morebar") )
>> {'bacon' : 'foobar'}
I also needed to select nested lists ;)
This can be done easily with #jellybean's solution:
def xpath_get(mydict, path):
elem = mydict
try:
for x in path.strip("/").split("/"):
try:
x = int(x)
elem = elem[x]
except ValueError:
elem = elem.get(x)
except:
pass
return elem
foo = {
'spam':'eggs',
'morefoo': [{
'bar':'soap',
'morebar': {
'bacon' : {
'bla':'balbla'
}
}
},
'bla'
]
}
print xpath_get(foo, "/morefoo/0/morebar/bacon")
[EDIT 2016] This question and the accepted answer are ancient. The newer answers may do the job better than the original answer. However I did not test them so I won't change the accepted answer.

One of the best libraries I've been able to identify, which, in addition, is very actively developed, is an extracted project from boto: JMESPath. It has a very powerful syntax of doing things that would normally take pages of code to express.
Here are some examples:
search('foo | bar', {"foo": {"bar": "baz"}}) -> "baz"
search('foo[*].bar | [0]', {
"foo": [{"bar": ["first1", "second1"]},
{"bar": ["first2", "second2"]}]}) -> ["first1", "second1"]
search('foo | [0]', {"foo": [0, 1, 2]}) -> [0]

There is an easier way to do this now.
http://github.com/akesterson/dpath-python
$ easy_install dpath
>>> dpath.util.search(YOUR_DICTIONARY, "morefoo/morebar")
... done. Or if you don't like getting your results back in a view (merged dictionary that retains the paths), yield them instead:
$ easy_install dpath
>>> for (path, value) in dpath.util.search(YOUR_DICTIONARY, "morefoo/morebar", yielded=True)
... and done. 'value' will hold {'bacon': 'foobar'} in that case.

Not exactly beautiful, but you might use sth like
def xpath_get(mydict, path):
elem = mydict
try:
for x in path.strip("/").split("/"):
elem = elem.get(x)
except:
pass
return elem
This doesn't support xpath stuff like indices, of course ... not to mention the / key trap unutbu indicated.

There is the newer jsonpath-rw library supporting a JSONPATH syntax but for python dictionaries and arrays, as you wished.
So your 1st example becomes:
from jsonpath_rw import parse
print( parse('$.morefoo.morebar').find(foo) )
And the 2nd:
print( parse("$.morefoo[0].morebar.bacon").find(foo) )
PS: An alternative simpler library also supporting dictionaries is python-json-pointer with a more XPath-like syntax.

dict > jmespath
You can use JMESPath which is a query language for JSON, and which has a python implementation.
import jmespath # pip install jmespath
data = {'root': {'section': {'item1': 'value1', 'item2': 'value2'}}}
jmespath.search('root.section.item2', data)
Out[42]: 'value2'
The jmespath query syntax and live examples: http://jmespath.org/tutorial.html
dict > xml > xpath
Another option would be converting your dictionaries to XML using something like dicttoxml and then use regular XPath expressions e.g. via lxml or whatever other library you prefer.
from dicttoxml import dicttoxml # pip install dicttoxml
from lxml import etree # pip install lxml
data = {'root': {'section': {'item1': 'value1', 'item2': 'value2'}}}
xml_data = dicttoxml(data, attr_type=False)
Out[43]: b'<?xml version="1.0" encoding="UTF-8" ?><root><root><section><item1>value1</item1><item2>value2</item2></section></root></root>'
tree = etree.fromstring(xml_data)
tree.xpath('//item2/text()')
Out[44]: ['value2']
Json Pointer
Yet another option is Json Pointer which is an IETF spec that has a python implementation:
https://github.com/stefankoegl/python-json-pointer
From the jsonpointer-python tutorial:
from jsonpointer import resolve_pointer
obj = {"foo": {"anArray": [ {"prop": 44}], "another prop": {"baz": "A string" }}}
resolve_pointer(obj, '') == obj
# True
resolve_pointer(obj, '/foo/another%20prop/baz') == obj['foo']['another prop']['baz']
# True
>>> resolve_pointer(obj, '/foo/anArray/0') == obj['foo']['anArray'][0]
# True

If terseness is your fancy:
def xpath(root, path, sch='/'):
return reduce(lambda acc, nxt: acc[nxt],
[int(x) if x.isdigit() else x for x in path.split(sch)],
root)
Of course, if you only have dicts, then it's simpler:
def xpath(root, path, sch='/'):
return reduce(lambda acc, nxt: acc[nxt],
path.split(sch),
root)
Good luck finding any errors in your path spec tho ;-)

Another alternative (besides that suggested by jellybean) is this:
def querydict(d, q):
keys = q.split('/')
nd = d
for k in keys:
if k == '':
continue
if k in nd:
nd = nd[k]
else:
return None
return nd
foo = {
'spam':'eggs',
'morefoo': {
'bar':'soap',
'morebar': {'bacon' : 'foobar'}
}
}
print querydict(foo, "/morefoo/morebar")

More work would have to be put into how the XPath-like selector would work.
'/' is a valid dictionary key, so how would
foo={'/':{'/':'eggs'},'//':'ham'}
be handled?
foo.select("///")
would be ambiguous.

Is there any reason for you to the query it the way like the XPath pattern? As the commenter to your question suggested, it just a dictionary, so you can access the elements in a nest manner. Also, considering that data is in the form of JSON, you can use simplejson module to load it and access the elements too.
There is this project JSONPATH, which is trying to help people do opposite of what you intend to do (given an XPATH, how to make it easily accessible via python objects), which seems more useful.

def Dict(var, *arg, **kwarg):
""" Return the value of an (imbricated) dictionnary, if all fields exist else return "" unless "default=new_value" specified as end argument
Avoid TypeError: argument of type 'NoneType' is not iterable
Ex: Dict(variable_dict, 'field1', 'field2', default = 0)
"""
for key in arg:
if isinstance(var, dict) and key and key in var: var = var[key]
else: return kwarg['default'] if kwarg and 'default' in kwarg else "" # Allow Dict(var, tvdbid).isdigit() for example
return kwarg['default'] if var in (None, '', 'N/A', 'null') and kwarg and 'default' in kwarg else "" if var in (None, '', 'N/A', 'null') else var
foo = {
'spam':'eggs',
'morefoo': {
'bar':'soap',
'morebar': {'bacon' : 'foobar'}
}
}
print Dict(foo, 'morefoo', 'morebar')
print Dict(foo, 'morefoo', 'morebar', default=None)
Have a SaveDict(value, var, *arg) function that can even append to lists in dict...

I reference form this link..
Following code is for json xpath base parse implemented in python :
import json
import xmltodict
# Parse the json string
class jsonprase(object):
def __init__(self, json_value):
try:
self.json_value = json.loads(json_value)
except Exception :
raise ValueError('must be a json str value')
def find_json_node_by_xpath(self, xpath):
elem = self.json_value
nodes = xpath.strip("/").split("/")
for x in range(len(nodes)):
try:
elem = elem.get(nodes[x])
except AttributeError:
elem = [y.get(nodes[x]) for y in elem]
return elem
def datalength(self, xpath="/"):
return len(self.find_json_node_by_xpath(xpath))
#property
def json_to_xml(self):
try:
root = {"root": self.json_value}
xml = xmltodict.unparse(root, pretty=True)
except ArithmeticError :
pyapilog().error(e)
return xml
Test Json :
{
"responseHeader": {
"zkConnected": true,
"status": 0,
"QTime": 2675,
"params": {
"q": "TxnInitTime:[2021-11-01T00:00:00Z TO 2021-11-30T23:59:59Z] AND Status:6",
"stats": "on",
"stats.facet": "CountryCode",
"rows": "0",
"wt": "json",
"stats.field": "ItemPrice"
}
},
"response": {
"numFound": 15162439,
"start": 0,
"maxScore": 1.8660598,
"docs": []
}
}
Test Code to read the values from above input json.
numFound = jsonprase(ABOVE_INPUT_JSON).find_json_node_by_xpath('/response/numFound')
print(numFound)