I am trying to convert a string to a dictionary with dict function, like this
import json
p = "{'id':'12589456'}"
d = dict(p)
print d['id']
But I get the following error
ValueError: dictionary update sequence element #0 has length 1; 2 is required
Why does it fail? How can I fix this?
What you have is a string, but dict function can only iterate over tuples (key-value pairs) to construct a dictionary. See the examples given in the dict's documentation.
In this particular case, you can use ast.literal_eval to convert the string to the corresponding dict object, like this
>>> p = "{'id':'12589456'}"
>>> from ast import literal_eval
>>> d = literal_eval(p)
>>> d['id']
'12589456'
Since p is a string containing JSON (ish), you have to load it first to get back a Python dictionary. Then you can access items within it:
p = '{"id":"12589456"}'
d = json.loads(p)
print d["id"]
However, note that the value in p is not actually JSON; JSON demands (and the Python json module enforces) that strings are quoted with double-quotes, not single quotes. I've updated it in my example here, but depending on where you got your example from, you might have more to do.
Related
I need to convert a string of list to List in Python. I have seen many of the similar questions but none of them works in this case.
I am passing some values through PostMan.
The key passing as a form data
Key = controls
value = [CR1,CR2]
I am fetching the data like this
c_list = self._kwargs['data'].get('controls', [])
print(c-list)
print(type(c-list))
I am getting the following o/p
[CC-2,CC-3]
<class 'str'>
But I need to get it as a list so I have tried the following method
import ast
c_list = self._kwargs['data'].get('controls', [])
res = ast.literal_eval(c_list)
But I am getting the following Error
malformed node or string: <_ast.Name object at 0x7f82966942b0>
You could simply do the following: strip the brackets and split on the commas
>>> s = "[CC-2,CC-3]"
>>> s.strip('[]').split(',')
['CC-2', 'CC-3']
the dataframe 'dataset' is automatically generated by PowerBI here is the result of my dataset.head(10).to_clipboard(sep=',', index=False)
coordinates,status
"[143.4865219,-34.7560602]",not started
"[143.4865241,-34.7561332]",not started
"[143.4865264,-34.7562088]",not started
"[143.4865286,-34.7562818]",not started
"[143.4865305,-34.7563453]",not started
"[143.4865327,-34.7564183]",not started
"[143.486535,-34.756494]",not started
"[143.4865371,-34.756567]",not started
"[143.486539,-34.7566304]",not started
"[143.4865412,-34.7567034]",not started
then to get the json
i do this data=dataset.to_json(orient='records')
which give me this results
[{"coordinates":"[143.4865219,-34.7560602]","status":"not started"},{"coordinates":"[143.4865241,-34.7561332]","status":"not started"},
how i get this instead , no quotes on the coordinates values
[{"coordinates":[143.4865219,-34.7560602],"status":"not started"},{"coordinates":[143.4865241,-34.7561332],"status":"not started"},
edit
print(type(data))
<class 'str'>
You could use ast.literal_eval:
Safely evaluate an expression node or a string containing a Python
literal or container display. The string or node provided may only
consist of the following Python literal structures: strings, bytes,
numbers, tuples, lists, dicts, sets, booleans, and None.
This can be used for safely evaluating strings containing Python
values from untrusted sources without the need to parse the values
oneself.[...]
Your data seems to be a string, and not a list as Python would print it (it uses single quotes by default, the double quotes in your data seem to indicate that it is a string, ready to be saved in a json file for example). So, you have to convert it first to a Python object with json.loads:
from ast import literal_eval
import json
data = """[{"coordinates":"[143.4865219,-34.7560602]","status":"not started"},{"coordinates":"[143.4865241,-34.7561332]","status":"not started"}]"""
data = json.loads(data)
for d in data:
d['coordinates'] = literal_eval(d['coordinates'])
print(data)
# [{'coordinates': [143.4865219, -34.7560602], 'status': 'not started'}, {'coordinates': [143.4865241, -34.7561332], 'status': 'not started'}]
import json
s = '[{"coordinates":"[143.4865219,-34.7560602]","status":"not started"},{"coordinates":"[143.4865241,-34.7561332]","status":"not started"}]'
d = json.loads(s)
d[0]['coordinates'] = json.loads(d[0]['coordinates'])
Applying this concept to every value can be done as in
for dic in d:
for key, value in dic.items():
try:
temp = json.loads(value)
if isinstance(temp, list):
dic[key] = temp
except Exception:
pass
or if you are sure there will be a coordinates key in ever dictionary
and that key having a "list" value
for dic in d: dic['coordinates'] = json.loads(dic['coordinates'])
simply u can use eval function.
new =[]
l = '[{"coordinates":"[143.4865219,-34.7560602]","status":"not started"},{"coordinates":"[143.4865241,-34.7561332]","status":"not started"}]'
l=eval(l)
for each_element in l:
temp={}
for k,v in each_element.items():
if k =='coordinates' :
temp[k]=eval(v)
else:
temp[k]=v
new.append(temp)
print(temp)
I am asked to generate and also later read back a json object which looks like:
{"name":"somename",
[{"id":123,"key1":"anydata"},
{"id":345,"key1":"x","key3":"yz"}]}
Normally, I would use a python dict and convert it to/from json. Here however is the problem, that both, list and sub-dict are anonymous.
I think it is not possible to make a dict like this, is it?
This is not a valid json object but you can just add a key for the list part. Like:
{"name":"somename","value" : [{"id":123,"key1":"anydata"},{"id":345,"key1":"x","key3":"yz"}]}
Now this is a valid json string.
>>> a = ast.literal_eval('{"name":"somename","value" : [{"id":123,"key1":"anydata"},{"id":345,"key1":"x","key3":"yz"}]}')
>>> print(a['name'])
>>> 'somename'
>>> print(a['value'][0]['id'])
>>> 123
For a variable list its is as simple as:
anon_list = [{"id":123,"key1":"anydata"},{"id":345,"key1":"x","key3":"yz"}]
a = {"name":"somename","value" : anon_list}
>>> print(a['name'])
>>> 'somename'
>>> print(a['value'][0]['id'])
>>> 123
I have data that look like this:
data = 'somekey:value4thekey&second-key:valu3-can.be?anything&third_k3y:it%can have spaces;too'
In a nice human-readable way it would look like this:
somekey : value4thekey
second-key : valu3-can.be?anything
third_k3y : it%can have spaces;too
How should I parse the data so when I do data['somekey'] I would get >>> value4thekey?
Note: The & is connecting all of the different items
How am I currently tackling with it
Currently, I use this ugly solution:
all = data.split('&')
for i in all:
if i.startswith('somekey'):
print i
This solution is very bad due to multiple obvious limitations. It would be much better if I can somehow parse it into a python tree object.
I'd split the string by & to get a list of key-value strings, and then split each such string by : to get key-value pairs. Using dict and list comprehensions actually makes this quite elegant:
result = {k:v for k, v in (part.split(':') for part in data.split('&'))}
You can parse your data directly to a dictionary - split on the item separator & then split again on the key,value separator ::
table = {
key: value for key, value in
(item.split(':') for item in data.split('&'))
}
This allows you direct access to elements, e.g. as table['somekey'].
If you don't have objects within a value, you can parse it to a dictionary
structure = {}
for ele in data.split('&'):
ele_split = ele.split(':')
structure[ele_split[0]] = ele_split[1]
You can now use structure to get the values:
print structure["somekey"]
#returns "value4thekey"
Since the keys have a common format of being in the form of "key":"value".
You can use it as a parameter to split on.
for i in x.split("&"):
print(i.split(":"))
This would generate an array of even items where every even index is the key and odd index being the value. Iterate through the array and load it into a dictionary. You should be good!
I'd format data to YAML and parse the YAML
import re
import yaml
data = 'somekey:value4thekey&second-key:valu3-can.be?anything&third_k3y:it%can have spaces;too'
yaml_data = re.sub('[:]', ': ', re.sub('[&]', '\n', data ))
y = yaml.load(yaml_data)
for k in y:
print "%s : %s" % (k,y[k])
Here's the output:
third_k3y : it%can have spaces;too
somekey : value4thekey
second-key : valu3-can.be?anything
Is there a simple way to create a dictionary from a list of formatted tuples. e.g. if I do something like:
d={"responseStatus":"SUCCESS","sessionId":"01234","userId":2000004904}
This creates a dictionary called d. However, if I want to create a dictionary from a string which contains the same string, I can't do that
res=<some command that returns {"responseStatus":"SUCCESS","sessionId":"01234","userId":2000004904}>
print res
# returns {"responseStatus":"SUCCESS","sessionId":"01234","userId":2000004904}
d=dict(res)
This throws an error that says:
ValueError: dictionary update sequence element #0 has length 1; 2 is required
I strongly strongly suspect that you have json on your hands.
import json
d = json.loads('{"responseStatus":"SUCCESS","sessionId":"01234","userId":2000004904}')
would give you what you want.
Use dict(zip(tuples))
>>> u = ("foo", "bar")
>>> v = ("blah", "zoop")
>>> d = dict(zip(u, v))
>>> d
{'foo': 'blah', 'bar': 'zoop'}
Note, if you have an odd number of tuples this will not work.
Based on what you gave is, res is
# returns {"responseStatus":"SUCCESS","sessionId":"01234","userId":2000004904}
So the plan is to grab the string starting at the curly brace to the end and use json to decode it:
import json
# Discard the text before the curly brace
res = res[res.index('{'):]
# Turn that text into a dictionary
d = json.loads(res)
All you need to do in your particular case is
d = eval(res)
And please keep security in mind when using eval, especially if you're mixing it with ajax/json.
UPDATE
Since others pointed out you might be getting this data over the web and it isn't just a "how to make this work" question, use this:
import json
json.loads(res)