I'm learning Python and I'm following official documentation from:
Section: 7.2.2. Saving structured data with json for Python 3
I'm testing the json.dump() function to dump my python set into a file pointer:
>>> response = {"success": True, "data": ["test", "array", "response"]}
>>> response
{'success': True, 'data': ['test', 'array', 'response']}
>>> import json
>>> json.dumps(response)
'{"success": true, "data": ["test", "array", "response"]}'
>>> f = open('testfile.txt', 'w', encoding='UTF-8')
>>> f
<_io.TextIOWrapper name='testfile.txt' mode='w' encoding='UTF-8'>
>>> json.dump(response, f)
The file testfile.txt already exists in my working directory and even if it didn't, statement f = open('testfile.txt', 'w', encoding='UTF-8') would have re-create it, truncated.
The json.dumps(response) converts my response set into a valid JSON object, so that's fine.
Problem is when I use the json.dumps(response, f) method, which actually updates my testfile.txt, but it gets truncated.
I've managed to do a reverse workaround like:
>>> f = open('testfile.txt', 'w', encoding='UTF-8')
>>> f.write(json.dumps(response));
56
>>>
After which the contents of my testfile.txt become as expected:
{"success": true, "data": ["test", "array", "response"]}
Even, this approach works too:
>>> json.dump(response, open('testfile.txt', 'w', encoding='UTF-8'))
Why does this approach fail?:
>>> f = open('testfile.txt', 'w', encoding='UTF-8')
>>> json.dump(response, f)
Note that I don't get any errors from the console; just a truncated file.
It looks like you aren't exiting the interactive prompt to check the file. Close the file to flush it:
f.close()
It will close if you exit the interactive prompt as well.
Related
I have the following content:
{
"z":"[{\"ItemId\":\"1234\",\"a\":\"1234\",\"b\":\"4567\",\"c\":\"d\"}]"
}
This is a part of the json response I get from a certain API. I need to replace the \"s with 's. Unfortunately, that's where I got stuck!
Most of the answers I get are simply replacing the \ with "" or " " so that did not help me. So my question are the following:
How can I replace the \" with ':
in a file where I copy-pasted the content?
if I receive this as a response to a certain API call?
I tried the following to replace the content in a file but I am clearly only replacing the "s with ':
with open(file, "r") as f:
content = f.read()
new_content = content.replace("\"", "'")
with open(file, "w") as new_file:
new_file.write(new_content)
If what you're trying to do is transform each value from a JSON string to a Python repr() string, while keeping the wrapper format as JSON, that might look like:
with open(filename, "r") as old_file:
old_content = json.load(old_file)
new_content = {k: repr(json.loads(v)) for k, v in old_content.items()}
with open(filename, "w") as new_file:
json.dump(new_content, new_file)
If your old file contains:
{"z":"[{\"ItemId\":\"1234\",\"a\":\"1234\",\"b\":\"4567\",\"c\":\"d\"}]"}
...the new file will contain:
{"z": "[{'ItemId': '1234', 'a': '1234', 'b': '4567', 'c': 'd'}]"}
Note that in this new file, the inner fields are now in Python format, not JSON format; they can no longer be parsed by JSON parsers. Usually, I would suggest doing something different instead, as in:
with open(filename, "r") as old_file:
old_content = json.load(old_file)
new_content = {k: json.loads(v) for k, v in old_content.items()}
with open(filename, "w") as new_file:
json.dump(new_content, new_file)
...which would yield an output file with:
{"z": [{"ItemId": "1234", "a": "1234", "b": "4567", "c": "d"}]}
...which is both easy-to-read and easy to process with standard JSON-centric tools (jq, etc).
Using json module, you can dumps the data then loads it using the following:
import json
data = {
"z": "[{\"ItemId\":\"1234\",\"a\":\"1234\",\"b\":\"4567\",\"c\":\"d\"}]"
}
g = json.dumps(data)
c = json.loads(data)
print(c)
print(str(c).replace("\"","'"))
Output:
{'z': '[{"ItemId":"1234","a":"1234","b":"4567","c":"d"}]'}
{'z': '[{'ItemId':'1234','a':'1234','b':'4567','c':'d'}]'}
When I export a file from python to json file it contains charecters like,
{"-": "text", "menu": {"-": "node", "id": 2244676, "prev": "[2/40] \u0d2a\u0d4d\u0d30\u0d2f\u0d4b\u0d1c\u0d15 \u0d15\u0d4d\u0d30\u0d3f\u0d2f
I used
with open('messages.json', 'w') as outfile:
json.dump(all_messages, outfile, cls=DateTimeEncoder)
in python. How to convert it to normal unicode text?
If you want the output JSON to be human-readable, use UTF-8 encoding and the ensure_ascii=False parameter:
with open('messages.json', 'w', encoding='utf8') as outfile:
json.dump(all_messages, outfile, cls=DateTimeEncoder,ensure_ascii=False)
If you just want to read the data back in again, json.load will convert it back to Unicode:
with open('messages.json', encoding='utf8') as infile:
data = json.load(infile)
Examples with simple strings:
>>> s = '[2/40] പ്രയോജക ക്രിയ'
>>> print(json.dumps(s))
"[2/40] \u0d2a\u0d4d\u0d30\u0d2f\u0d4b\u0d1c\u0d15 \u0d15\u0d4d\u0d30\u0d3f\u0d2f"
>>> print(json.dumps(s,ensure_ascii=False))
"[2/40] പ്രയോജക ക്രിയ"
>>> out = json.dumps(s)
>>> out
'"[2/40] \\u0d2a\\u0d4d\\u0d30\\u0d2f\\u0d4b\\u0d1c\\u0d15 \\u0d15\\u0d4d\\u0d30\\u0d3f\\u0d2f"'
>>> json.loads(out)
'[2/40] പ്രയോജക ക്രിയ'
I have the following python script (it 'converts' xml to for example json):
import xmltodict
import pprint
import json
with open('file.xml') as fd:
doc = xmltodict.parse(fd.read())
pp = pprint.PrettyPrinter(indent=4)
pp.pprint(json.dumps(doc))
When I run the following code it will output the json code. Question is; how can I write the output to output.json instead of the output to the screen?
Thanks!
To format json with indents you can use indent argument (link to docs).
with open('file.xml', 'r') as src_file, open('file.json', 'w+') as dst_file:
doc = xmltodict.parse(src_file.read()) #read file
dst_file.write(json.dumps(doc, indent=4)) #write file
To print Json into file
with open("your_output_file.json", "w+") as f:
f.write(json.dumps(doc))
To read JSON from file
with open("your_output_file.json") as f:
d = json.load(f)
To write your dictionary dct to a file, use json.dump
with open("output.json", "w+") as f:
json.dump(dct,f)
To read your dictionary from a file, use json.load
with open("output.json", "w+") as f:
dct = json.load(f)
Combining both examples
In [8]: import json
In [9]: dct = {'a':'b','c':'d'}
In [10]: with open("output.json", "w") as f:
...: json.dump(dct,f)
...:
In [11]: with open("output.json", "r") as f:
...: print(json.load(f))
...:
...:
{'a': 'b', 'c': 'd'}
I want to save my python to json file, but the thing is, I need to name my json file's name as title's name.
code:
data={
"Title" : title.text,
"Registration": doctor.text,
"Keywords": list2,
"Article": list
}
#title.text="banana"
with open('title.text.json', 'w',encoding='UTF-8') as f:
json.dump(data, f,ensure_ascii=False)
The result I expected: Save it as banana.json
Edit:
It works with this
with open('%s.json' % title_tag.text, 'w',encoding='UTF-8') as f:
json.dump(data, f,ensure_ascii=False)
you can use the following code to achieve this:
with open(title.text, 'w', encoding='UTF-8') as f:
json.dump(data, f, ensure_ascii=False)
I have the following code that will write to a JSON file:
import json
def write_data_to_table(word, hash):
data = {word: hash}
with open("rainbow_table\\rainbow.json", "a+") as table:
table.write(json.dumps(data))
What I want to do is open the JSON file, add another line to it, and close it. How can I do this without messing with the file?
As of right now when I run the code I get the following:
write_data_to_table("test1", "0123456789")
write_data_to_table("test2", "00123456789")
write_data_to_table("test3", "000123456789")
#<= {"test1": "0123456789"}{"test2": "00123456789"}{"test3": "000123456789"}
How can I update the file without completely screwing with it?
My expected output would probably be something along the lines of:
{
"test1": "0123456789",
"test2": "00123456789",
"test3": "000123456789",
}
You may read the JSON data with :
parsed_json = json.loads(json_string)
You now manipulate a classic dictionary. You can add data with :
parsed_json.update({'test4': 0000123456789})
Then you can write data to a file using :
with open('data.txt', 'w') as outfile:
json.dump(parsed_json, outfile)
If you are sure the closing "}" is the last byte in the file you can do this:
>>> f = open('test.json', 'a+')
>>> json.dump({"foo": "bar"}, f) # create the file
>>> f.seek(0)
>>> f.read()
'{"foo": "bar"}'
>>> f.seek(-1, 2)
>>> f.write(',\n', f.write(',\n' + json.dumps({"spam": "bacon"})[1:]))
>>> f.seek(0)
>>> print(f.read())
{"foo": "bar",
"spam": "bacon"}
Since your data is not hierarchical, you should consider a flat format like "TSV".