Develop Reference

How to append value inside list in json?

I am trying to append value inside the list,but whenever I re run the server it overwrites the value. How can I effectively write in the json file.
{
"heart_rate": [
72.18
],
"Experiment_time": [
01/22/2023 11:59:59
]
}
I want to add values in json file, When ever I get new value it should get append inside the heartrate and Experiment_time list inside the corresponding keys, similar to below mentioned format.
{
"heart_rate": [
72.18,73.44
],
"Experiment_time": [
01/22/2023 11:59:59,01/22/2023 11:60:00
]
}
What I am tring is to first read the json file if it exists, If it doesn't create one.
try:
with open('Accounts.json','r') as fp:
data = json.load(fp)
f = data
print(f)
heartrate,dt_string = perform_all()
lst1 = []
if f != '':
print("something")
else:
lst1.append(heartrate)
except :
print("File Not found. Creating One")
data = {}
data['heart_rate'] = [None]
data['Experiment_time'] = [None]
with open('Accounts.json','w') as fp:
json.dump(data,fp,indent = 4)
heartrate,dt_string = perform_all()
is a function that returns 1 value of heartrate and 1 value of datetime when called

Close, just append to the right dictionary key. Note that JSON should be encoded in UTF-8 and not all OSes default to that encoding. It will matter if you write non-ASCII characters. Also bare except is a bad practice. Put the exception you expect.
import json
import datetime as dt
def perform_all():
return 85, dt.datetime.now().strftime('%m/%d/%y %H:%M:%S')
try:
with open('Accounts.json', encoding='utf8') as fp:
data = json.load(fp)
heartrate, dt_string = perform_all()
data['heart_rate'].append(heartrate)
data['Experiment_time'].append(dt_string)
except FileNotFoundError:
print('File not found. Creating initial data...')
data = {'heart_rate': [], 'Experiment_time': []}
with open('Accounts.json', 'w', encoding='utf8') as fp:
json.dump(data, fp, indent=2)
Output:
C:\>test
File not found. Creating one...
C:\>test
C:\>test
C:\>type Accounts.json
{
"heart_rate": [
85,
85
],
"Experiment_time": [
"01/26/23 21:34:22",
"01/26/23 21:34:23"
]
}

Python - get a LIST value from field in JSON

I have a JSON file containing three fields: 2 are strings and third one is field containing a list of values.
{ "STREAM": "stream",
"BASIS_STREAM": "basis",
"PATHS": "[/opt/path1,/opt/path2]"
}
Now I load that JSON
with open('/pathToJsonFile.json', 'r') as f:
data = json.load(f)
Now I want to get those values.
stream=str(data["STREAM"])
basis=str(data["BASIS_STREAM"])
paths=data["BASE_PATHS"]
The issue is that paths is also threated as String, although I have to use it as a list. I am converting with str function other fields because of the Unicode. Code must be in python2.
Thanks a lot!

Say you have a file called data.json with the following contents:
{
"STREAM": "stream",
"BASIS_STREAM": "basis",
"PATHS": "[/opt/path1,/opt/path2]"
}
Maybe you could use str.split after calling json.load:
with open('data.json', 'r') as f:
data = json.load(f)
print 'data = %s' % data
stream = str(data['STREAM'])
basis = str(data['BASIS_STREAM'])
paths = [str(u_s) for u_s in data['PATHS'][1:-1].split(',')]
print 'stream = %s' % stream
print 'basis = %s' % basis
print 'paths = %s' % paths
Output:
data = {u'PATHS': u'[/opt/path1,/opt/path2]', u'BASIS_STREAM': u'basis', u'STREAM': u'stream'}
stream = stream
basis = basis
paths = ['/opt/path1', '/opt/path2']

Your /opt/path1 and /opt/path2 should be in a quotation marks to be converted in a list. If your PATHS always have a similar template such as "[/XXX,/YYY,/ZZZ,/TTT,/KKK]" the following code should also help. I have converted your data as "['/XXX','/YYY','/ZZZ','/TTT','/KKK']" so that it can be easily converted to a list using ast library. Please see the code as following:
import json
import ast
with open("text_text.json") as f:
data = json.load(f)
print(data["PATHS"]) # Your data
for i in data["PATHS"]:
if i == "[":
data["PATHS"] = data["PATHS"].replace("[", "['")
elif i == ",":
data["PATHS"] = data["PATHS"].replace(",/", "','/")
elif i == "]":
data["PATHS"] = data["PATHS"].replace("]", "']")
#print(data["PATHS"])
print(type(data["PATHS"]))
print(data["PATHS"]) #converted to a data which can be converted to a list.
data_paths = ast.literal_eval(data["PATHS"]) # ast is used to convert str to list.
print(data_paths) # 'list' data
print(type(data_paths))
See the output of the code:
It should also work if your PATH has more data as following:

PYTHON: reading .jl file using jsonlines is resulting in line of json. I need all the json lines

I am trying to read the file from the path and add to the dictionary, however, i end up with first json-line and there are about 230MB of data.
I have folder like here
# folder path
folder = os.path.expanduser("~/topic_2022-05-30T23-15-20.jl")
#Initialise the dictionary
items = {}
with open(folder, 'rb') as f:
for item in json_lines.reader(f):
# adding next item to items
items.update(item)

import json
file = open(folder)
items = {}
data = json.load(file)
for k, v in data.items():
items.update(k:v)
file.close()
itmes = data could also work.

how to append text to file in specific location in python3?

i'm trying to append text to file in specific location.
i want to create program which takes input from user(name, image, id) and adds them to this file
names = []
images = []
id = 0
url = ['https://somewebsiteUsingId10.com',
'https://somewebsiteUsingId20.com']
if id == 5:
names.append("Testing Names")
images.append("Testing Images")
elif id == 0:
names.append("Testing one names")
images.append("Testing one Images")
I want modified file to be like this:
names = []
images = []
id = 0
url = ['https://somewebsiteUsingId20.com',
'https://somewebsiteUsingId10.com',
'https://somewebsiteUsingId50.com']
if id == 5:
names.append("Testing Names")
images.append("Testing Images")
elif id == 0:
names.append("Testing one names")
images.append("Testing one Images")
elif id == 50:
names.append("User input")
images.append("User Input")
Thanks!

In cases like this, a good course of action is to put the variable data in a configuration file.
On start-up, your program reads the configuration file and processes it.
Another program can update the configuration file.
Python has the json module in its standard library. This supports lists and dicts, so it is a good match for Python data structures.
Say you write a file urls.json, looking like this:
[
"https://somewebsiteUsingId20.com",
"https://somewebsiteUsingId10.com",
"https://somewebsiteUsingId50.com"
]
In your program you can then do:
import json
with open("urls.json") as f:
urls = json.load(f)
The variable urls now points to a list containing the aforementioned URLs.
Writing the config data goes about the same:
urls = [
"https://www.parrot.org",
"https://www.ministryofsillywalks.org",
"https://www.cheese.net",
]
with open("newurls.json", "w") as f:
json.dump(urls, f, indent=4)
The file newurls.json now contains:
[
"https://www.parrot.org",
"https://www.ministryofsillywalks.org",
"https://www.cheese.net"
]
Note that JSON is pretty flexible, you are not limited to strings:
import datetime
config = {
'directories': ["https://www.parrot.org", "https://www.ministryofsillywalks.org"],
'saved': str(datetime.datetime.now()),
'count': 12
}
with open("configuration.json", "w") as cf:
json.dump(config, cf, indent=4)
This would result in something like:
{
"directories": [
"https://www.parrot.org",
"https://www.ministryofsillywalks.org"
],
"saved": "2022-02-07 21:21:14.787420",
"count": 12
}
(You'd get another date/time, of course.)
The only major downside to JSON files is that they don't allow comments. If you need comments, use another format like the configparser module.
Note that there are other methods like shelve and read&eval but those have potential safety issues.

storing for loop iteration data

I am playing with cgi (uploading file form),
and I am receiving the files as storage object and I sotred it in (input) variable.
this is the simple iteration.
for file in input:
filepath = ....
filename, fileext = os.path.splitext(filepath)
file_real_name = ....
file_size = ....
file_type = ...
file_url = ....
file_short_name = ...
file_show_link = ....
# etc
it would be easy if it was only one file , but what If i have more than one ?
how can I have another value that holds all the iteration information in
like uploaded_files where I can access each uploaded file with all the information for the above iteration ?
I tried to read the docs but I cant wrap my head around some iteration concepts yet, sorry :)

You want to use a data structure to hold your data. Depending on the complexity, you may want to simply use a list of dictionaries:
files = []
for file in input:
files.append({
"path": get_path(file),
"name": get_name(file),
"size": get_size(file),
...
})
Or, if you find you need to perform lots of operations on your data, you might want to make your own class and make a list of objects:
class SomeFile:
def __init__(self, path, name, size, ...):
self.path = path
...
def do_something_with_file(self):
...
files = []
for file in input:
files.append(SomeFile(get_path(file), get_name(file), get_size(file), ...))
Note that here you are following a pattern of building up a list by iterating over an iterator. You can do this efficiently using a list comprehension, e.g:
[{"path": get_path(file), "name": get_name(file), ...} for file in input]
Also note that file and input are really bad variable names, as they will mask the builtins file() and input().

results = []
for i in range(5):
file_data = {}
file_data['a'] = i
file_data['b'] = i**2
results.append(file_data)
print results