So I have a generated JSON which one looks like ( there is a lot of it just with unique ID )
{
"id": 1,
"name": "name",
"dep": "dep",
"Title": "Title',
"email": "email"
}
I'm trying to do "append" a new field but I get an error
with open('data.json', 'w') as file:
json.dump(write_list, file)
file.close()
with open('data.json', 'w') as json_file:
entry = {'parentId': random.randrange(0, 487, 2)}
json_file.append(entry, json_file)
json_file.close()
It there is some way to add one more "key: value" to it after generating ?
There are two issues:
your are using json.dump to generate a list, but you're not using json.load to re-create the Python data structure.
You're opening the file with the w mode in the second open call, which truncates it
Try breaking each step out into its own and separating mutating data and writing to disk.
with open('data.json', 'w') as file:
json.dump(write_list, file)
#file.close() # manually closing files is unnecessary,
# when using context managers
with open('data.json', 'r') as json_file:
write_list = json.load(json_file)
entry = {'parentId': random.randrange(0, 487, 2)}
write_list.append(entry)
with open('data.json', 'w') as json_file:
json.dump(write_list, file)
The steps to do what you want are as files:
Parse the entire JSON file into a python dictionary.
Add the entry to the dictionary.
Serialize the string back to JSON.
Write the JSON file back to the file.
Also after I done this feature with Tim McNamara advice, I found a more pretty way to add new line to every JSON dict I have in file
for randomID in write_list:
randomID['parentId'] = random.randrange(0, 487, 2)
with open('data.json', 'w') as file:
json.dump(write_list, file)
Related
Firstly, here is my JSON file structure
[{
"title": "Reference Addition",
"ref_date": 20200110,
"country": "ASIA",
"ref_internal": "1",
"ref_external": "1"
}]
I have code where I have successfully loaded the file in Python. I want to change the value of country and save it to a new file.
with open('myfile.json', 'r') as f:
json_data = json.load(f)
json_data['country'] = 'AFRICA'
with open('myfile.json', 'w') as f:
json.dump(json_data, f, indent=2)
But unfortunately I keep getting
AttributeError: module 'json' has no attribute 'tree'
searched something online after which i manage to resolve that Error but now hitting this Error
import json
myfile = ('JSON\TRADE.json')
with open (myfile, 'r') as myfile: json_data = json.load(myfile) json_data['country'] = 'AFRICA'
json.tree.dump(json_data, indent=4)
with open(myfile, 'w') as f: json.dump(json_data, f, indent=4)
error now with full traceback is
Traceback (most recent call last):
File "c:\AUTOMATION\Data Creation\JSON\EDIT.py", line 7, in json_data['country'] = 'AFRICA' TypeError: list indices must be integers or slices, not str PS C:\AUTOMATION\Data Creation>
Apologies if any detail is not correct but please let me know so i can provide
The issue is with the JSON file structure. It looks like your JSON file is an array of objects, each containing the properties you listed. In order to access the country property, you need to first access the object within the array. You can do this by specifying the index of the object, like this:
with open(myfile, 'r') as f:
json_data = json.load(f)
json_data[0]['country'] = 'AFRICA'
with open(myfile, 'w') as f:
json.dump(json_data, f, indent=4)
This will change the value of the country property of the first object in the array to "AFRICA".
Also, in your code, it is not necessary to use json.tree, it is just json.dump to save the data in the file.
I want to write data to a json file. If it does not exists, I want to create that file, and write data to it. I wrote code for it, but I'm getting json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0).
Here's part of my code:
data = {"foo": "1"}
with open("file.json", "w+") as f:
try:
file_data = json.load(f)
json.dump(data, f)
print("got data from file:", file_data)
except json.decoder.JSONDecodeError:
json.dump(data, f)
print("wrote")
I put print statements so that I can "track" what's going on, but If I try to run this code multiple times, I keep getting wrote message.
Thanks in advance for help!
The problem is that you open the file for write/read therefore once you open the file it will be emptied.
Then you want to load the content with json.load and it obviously fails because the file is not a valid JSON anymore.
So I'd suggest to open the file for reading and writing separately:
import json
with open("file.json") as json_file:
file_data = json.load(json_file)
print("got data from file:", file_data)
data = {"foo": "1"}
with open("file.json", "w") as json_file:
json.dump(data, json_file)
Hope it helps!
Is there a way to append single JSON objects to a json file while in a for loop in python. I would prefer not store all my data in one giant json object and dump it all at once, as I am planning on performing millions of API requests. I would like to make a single API request, dump the result into a JSON file and then move to the next API request and dump that into the same JSON file.
The below code overwrites the JSON file, I am looking for something that appends.
for url in urls:
r = sesh.get(url)
data = r.json()
with open('data.json', 'w') as outfile:
json.dump(data, outfile)
Such that:
with open('data.json') as outfile:
data = json.load(data, outfile)
type(data)
>> dict
r.json looks something like this:
{'attribute1':1, 'attribute2':10}
Update
Well since I don't have access to your API I just placed some sample responses, in the format you supplied, inside an array.
import json
urls = ['{"attribute1":1, "attribute2":10}', '{"attribute1":67, "attribute2":32}', '{"attribute1":37, "attribute2":12}'];
json_arr = []
for url in urls:
data = json.loads(url)
json_arr.append(data)
with open('data.json', 'w') as outfile:
json.dump(json_arr, outfile)
Basically we keep an array and append each API response to that array. Then, we can write the accumulative JSON to a file. Also if you want to update the same JSON file on different executions of the code, you can just read the existing output file into an array, in the beginning of the code, and then carry on with my example.
Change write mode to append
Try changing this:
with open('data.json', 'w') as outfile:
To this:
with open('data.json', 'a') as outfile:
The previous answer is surprisingly close to what you need to do.
So I will build upon it.
import json
json_arr = ['{"attribute1":1, "attribute2":10}', '{"attribute1":67, "attribute2":32}', '{"attribute1":37, "attribute2":12}'];
with open('data.json', 'w') as outfile:
outfile.write('[')
for element in json_arr:
with open('data.json', 'w') as outfile:
json.dump(element, outfile)
outfile.write(',')
with open('data.json', 'a') as outfile:
outfile.write(']')
I'm working with python, I have a json structure into a dictionary and I have exported it into a file. Now I need to reload the structure from the file, I want to reload it into a dictionary (in order to update it) but I'm experiencing some problems. This is my code:
#export the structure
with open('data.json','w') as f:
data = {}
data['test'] = '1'
f.write(json.dumps(data))
#reload the structure
with open('data.json','r') as f:
dict = {}
dict = json.loads(f.read())
The error is: No JSON object could be decoded.
Try
with open('data.json', 'w') as f:
f.write(json.dumps(data))
with open('data.json', 'r') as f:
json.load(f)
I am new to Python and I am playing with JSON data. I would like to retrieve the JSON data from a file and add to that data a JSON key-value "on the fly".
That is, my json_file contains JSON data as-like the following:
{"key1": {"key1A": ["value1", "value2"], "key1B": {"key1B1": "value3"}}}
I would like to add the "ADDED_KEY": "ADDED_VALUE" key-value part to the above data so to use the following JSON in my script:
{"ADDED_KEY": "ADDED_VALUE", "key1": {"key1A": ["value1", "value2"], "key1B": {"key1B1": "value3"}}}
I am trying to write something as-like the following in order to accomplish the above:
import json
json_data = open(json_file)
json_decoded = json.load(json_data)
# What I have to make here?!
json_data.close()
Your json_decoded object is a Python dictionary; you can simply add your key to that, then re-encode and rewrite the file:
import json
with open(json_file) as json_file:
json_decoded = json.load(json_file)
json_decoded['ADDED_KEY'] = 'ADDED_VALUE'
with open(json_file, 'w') as json_file:
json.dump(json_decoded, json_file)
I used the open file objects as context managers here (with the with statement) so Python automatically closes the file when done.
Json returned from json.loads() behave just like native python lists/dictionaries:
import json
with open("your_json_file.txt", 'r') as f:
data = json.loads(f.read()) #data becomes a dictionary
#do things with data here
data['ADDED_KEY'] = 'ADDED_VALUE'
#and then just write the data back on the file
with open("your_json_file.txt", 'w') as f:
f.write(json.dumps(data, sort_keys=True, indent=4, separators=(',', ': ')))
#I added some options for pretty printing, play around with them!
For more info check out the official doc
You can do
json_decoded['ADDED_KEY'] = 'ADDED_VALUE'
OR
json_decoded.update({"ADDED_KEY":"ADDED_VALUE"})
which works nicely if you want to add more than one key/value pair.
Of course, you may want to check for the existence of ADDED_KEY first - depends on your needs.
AND I assume you want might want to save that data back to the file
json.dump(json_decoded, open(json_file,'w'))