I want to append onto an employees history every time they clock in. I have appended within python but cant get it to write back to the JSON file.
import json
json_data = open("app.json")
data = json.load(json_data)
for d in data['employees']:
d['history'].append({'day': 01.01.15, 'historyId': 44, 'time': 12.00})
json.dump(d['history'])
json.dump() takes two arguments, the Python object to dump and the file to write it to.
Make your changes first, then after the loop, re-open the file for writing and write out the whole data object:
with open("app.json") as json_data:
data = json.load(json_data)
for d in data['employees']:
d['history'].append({'day': 01.01.15, 'historyId': 44, 'time': 12.00})
with open("app.json", 'w') as json_data:
json.dump(data, json_data)
This essentially replaces the file contents with the JSON-serialised new data structure.
Related
The goal is to open a json file or websites so that I can view earthquake data. I create a json function that use dictionary and a list but within the terminal an error appears as a invalid argument. What is the best way to open a json file using python?
import requests
`def earthquake_daily_summary():
req = requests.get("https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson")
data = req.json() # The .json() function will convert the json data from the server to a dictionary
# Open json file
f = open('https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson')
# returns Json oject as a dictionary
data = json.load(f)
# Iterating through the json
# list
for i in data['emp_details']:
print(i)
f.close()
print("\n=========== PROBLEM 5 TESTS ===========")
earthquake_daily_summary()`
You can immediately convert the response to json and read the data you need.
I didn't find the 'emp_details' key, so I replaced it with 'features'.
import requests
def earthquake_daily_summary():
data = requests.get("https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson").json()
for row in data['features']:
print(row)
print("\n=========== PROBLEM 5 TESTS ===========")
earthquake_daily_summary()
I apologize for the vague definition of my problem in the title, but I really can't figure out what sort of problem I'm dealing with. So, here it goes.
I have python file:
edit-json.py
import os, json
def add_rooms(data):
if(not os.path.exists('rooms.json')):
with open('rooms.json', 'w'): pass
with open('rooms.json', 'r+') as f:
d = f.read() # take existing data from file
f.truncate(0) # empty the json file
if(d == ''): rooms = [] # check if data is empty i.e the file was just created
else: rooms = json.loads(d)['rooms']
rooms.append({'name': data['roomname'], 'active': 1})
f.write(json.dumps({"rooms": rooms})) # write new data(rooms list) to the json file
add_rooms({'roomname': 'friends'})'
This python script basically creates a file rooms.json(if it doesn't exist), grabs the data(array) from the json file, empties the json file, then finally writes the new data into the file. All this is done in the function add_rooms(), which is then called at the end of the script, pretty simple stuff.
So, here's the problem, I run the file once, nothing weird happens, i.e the file is created and the data inside it is:
{"rooms": [{"name": "friends"}]}
But the weird stuff happens when the run the script again.
What I should see:
{"rooms": [{"name": "friends"}, {"name": "friends"}]}
What I see instead:
I apologize I had to post the image because for some reason I couldn't copy the text I got.
and I can't obviously run the script again(for the third time) because the json parser gives error due to those characters
I obtained this result in an online compiler. In my local windows system, I get extra whitespace instead of those extra symbols.
I can't figure out what causes it. Maybe I'm not doing file handling incorrectly? or is it due to the json module? or am I the only one getting this result?
When you truncate the file, the file pointer is still at the end of the file. Use f.seek(0) to move back to the start of the file:
import os, json
def add_rooms(data):
if(not os.path.exists('rooms.json')):
with open('rooms.json', 'w'): pass
with open('rooms.json', 'r+') as f:
d = f.read() # take existing data from file
f.truncate(0) # empty the json file
f.seek(0) # <<<<<<<<< add this line
if(d == ''): rooms = [] # check if data is empty i.e the file was just created
else: rooms = json.loads(d)['rooms']
rooms.append({'name': data['roomname'], 'active': 1})
f.write(json.dumps({"rooms": rooms})) # write new data(rooms list) to the json file
add_rooms({'roomname': 'friends'})
I am trying to read a JSON file (BioRelEx dataset: https://github.com/YerevaNN/BioRelEx/releases/tag/1.0alpha7) in Python. The JSON file is a list of objects, one per sentence.
This is how I try to do it:
def _read(self, file_path):
with open(cached_path(file_path), "r") as data_file:
for line in data_file.readlines():
if not line:
continue
items = json.loads(lines)
text = items["text"]
label = items.get("label")
My code is failing on items = json.loads(line). It looks like the data is not formatted as the code expects it to be, but how can I change it?
Thanks in advance for your time!
Best,
Julia
With json.load() you don't need to read each line, you can do either of these:
import json
def open_json(path):
with open(path, 'r') as file:
return json.load(file)
data = open_json('./1.0alpha7.dev.json')
Or, even cooler, you can GET request the json from GitHub
import json
import requests
url = 'https://github.com/YerevaNN/BioRelEx/releases/download/1.0alpha7/1.0alpha7.dev.json'
response = requests.get(url)
data = response.json()
These will both give the same output. data variable will be a list of dictionaries that you can iterate over in a for loop and do your further processing.
Your code is reading one line at a time and parsing each line individually as JSON. Unless the creator of the file created the file in this format (which given it has a .json extension is unlikely) then that won't work, as JSON does not use line breaks to indicate end of an object.
Load the whole file content as JSON instead, then process the resulting items in the array.
def _read(self, file_path):
with open(cached_path(file_path), "r") as data_file:
data = json.load(data_file)
for item in data:
text = item["text"]
label appears to be buried in item["interaction"]
I have a dictionary, for example:
a = {'a':1,'b':2,'c':3}
And I want it to be saved in a json file.
How can I do this with the original python json library?
Please note that I am running Python 3.5.2, which has a build-in json library.
You can also dump json file directly using json.dump instead of json.dumps.
import json
a = {'a':1,'b':2,'c':3}
with open("your_json_file", "w") as fp:
json.dump(a , fp)
json.dumps is mainly used to display dictionaries as a json format with the type of string. While dump is used for saving to file. Using this to save to file is obsolete.
The previous example only save the file to json but does not make it very pretty. So instead you could do this:
json.dump(a, fp, indent = 4) # you can also do sort_keys=True as well
# this work the same for json.dumps
This makes the json file more user friendly to read. the pydoc has some good description on how to use the json module.
To retrieve your data back, you can use the load function.
a = json.load(fp) # load back the original dictionary
This may help you...
import json
a = {'name': 'John Doe', 'age': 24}
js = json.dumps(a)
# Open new json file if not exist it will create
fp = open('test.json', 'a')
# write to json file
fp.write(js)
# close the connection
fp.close()
show you code
#!/usr/bin/env python
# coding:utf-8
'''黄哥Python'''
import json
a = {'a': 1, 'b': 2, 'c': 3}
with open("json.txt", "w") as f:
f.write(json.dumps(a))
check this-
import json
a = {'a':1,'b':2,'c':3}
json_str = json.dumps(a)
with open('data.json', 'w') as f:json.dump(data, f)
Most of other answers are correct but this will also print data in prettify and sorted manner.
import json
a = {'name': 'John Doe', 'age': 24}
js = json.dumps(a, sort_keys=True, indent=4, separators=(',', ': '))
with open('test.json', 'w+') as f:
f.write(js)
I am using Python and I have a JSON file in which I would like to update a value related to a given key. That is, I have the my_file.json containing the following data
{"a": "1", "b": "2", "c": "3"}
and I would like to just change the value related to the b key from 2 to 9 so that the updated file look as like:
{"a": "1", "b": "9", "c": "3"}
How can I make that?
I tried the following but without success (the changes are not saved to the file):
with open('my_file.json', 'r+') as f:
json_data = json.load(f)
json_data['b'] = "9"
f.close()
You did not save the changed data at all. You have to first load, then modify, and only then save. It is not possible to modify JSON files in-place.
with open('my_file.json', 'r') as f:
json_data = json.load(f)
json_data['b'] = "9"
with open('my_file.json', 'w') as f:
f.write(json.dumps(json_data))
You may also do this:
with open('my_file.json', 'r+') as f:
json_data = json.load(f)
json_data['b'] = "9"
f.seek(0)
f.write(json.dumps(json_data))
f.truncate()
If you want to make it safe, you first write the new data into a temporary file in the same folder, and then rename the temporary file onto the original file. That way you will not lose any data even if something happens in between.
If you come to think of that, JSON data is very difficult to change in-place, as the data length is not fixed, and the changes may be quite significant.
You are almost there, you only have to write the updated json_data back to the file. Get rid of f.close(), as the with statement will ensure that the file is closed. Then, issue
with open('my_file.json', 'w') as f:
f.write(json.dumps(json_data))
This is simplest way to do the json file updation/writing.
where you are creating instance of json file as 'f' and the writing the 'data' into the json file,
#write json file
with open('data.json', 'w') as f:
json.dump(data, f)
#Read json file
with open('data.json', 'r') as f:
json.load(data, f)
Open the file and store in one variable all the content using json.load function
Update your key stored in the previous variable
Open the file another time and update your content with the variable updated
def updateJsonFile():
jsonFile = open("my_file.json", "r") # Open the JSON file for reading
data = json.load(jsonFile) # Read the JSON into the buffer
jsonFile.close() # Close the JSON file
## Working with buffered content
data["b"] = "9"
## Save our changes to JSON file
jsonFile = open("my_file.json", "w+")
jsonFile.write(json.dump(data))
jsonFile.close()