I've search a ton of articles here and elsewhere via the Googles, plus read a few related docs over at docs.python.org and still stuck.
I am getting a response from an API like below:
{"status":"active","perms":1,"data":{"40332895":{"user_values":{"delta":-203,"value":53.32,"order":42509}}}}
I have no problem printing the 'status' or 'data'. However, all I can grab is the name of the *user_values*, not the date inside them.
Been at it for way to long and was hoping someone could point me in the right direction. Fairly new to Python and if I need to change how I am doing this because it is bad practices or there is an easier way to get the results I am looking for, please let me know.
Code:
import json
import urllib2
url = urllib2.urlopen('http://URLofAPI.com')
json_url = json.load(url)
api_result = json_url
for doc in api_result['data']['40332895']['user_values']:
print doc
outputs:
delta
value
order
what I really want to get is the value of them (i.e.: '-203', '53.32', '42509').
I am basically trying to save that data into a list\dict (individually or separately), then print it with other data. I have tried all sorts of things and cannot manage it. I am sure it's probably something super easy that I missing, but it's driving me nuts. :)
Also, I was really expecting the below to give me '42509', but I get an error:
for doc in api_result['data']['40332895']['user_values']['order']
Thanks in advance!
You're asking for the keys of the user_values dictionary, and getting them. Try this:
uv = api_result['data']['40332895']['user_values']
for doc in uv:
print uv[doc]
In your example api_result['data']['40332895']['user_values'] is a dictionary.
If you iterate over a dictionary you will get the keys. This is the case in your original example and in mgkrebbs answer.
However if you iterate over the .iteritems() (or .items()) of the dictionary you get the (key, value) pairs in a tuple:
uv = api_result['data']['40332895']['user_values']
for key,value in uv.iteritems():
print key, value
If you only need the values, you iterate over .itervalues()
uv = api_result['data']['40332895']['user_values']
for value in uv.itervalues():
print value
Or if you only need the values as a list:
my_list = api_result['data']['40332895']['user_values'].values()
The difference between .itervalues() and .values() is that the former gives you an iterable (an object which returns one value at a time, but does not create the structure in memory), while the latter gives you a list.
Related
Might be a dumb question or a small typo. I'm iterating through a JSON object I loaded in and my goal is to MTL some text deep inside. I'm iterating through a list of objects for a specified code, then I translate the text on a correct match. So Iterate through objects > Match Code > Translate Text
The problem is when I try to alter the object by replacing the text with the translated version, that data isn't changed in the returned data object.
def findMatch(data):
# Search Events
for event in data['events']:
if (event is not None):
pages = event['pages']
for page in pages:
lists = page['list']
for list in lists:
if(list['code'] == 401):
for parameter in list['parameters']:
parameter = checkLine(parameter)
return data
checkLine(parameter) will return a string of the text translated.
I'm guessing parameter isn't connected to the data object which is why it's not working but unsure how exactly it should be written out.
Also any suggestions on how to make this faster/more efficient are welcome.
for i, parameter in enumerate(list['parameters']):
list['parameters'][i] = checkLine(parameter)
Does the trick.
So basically I'm at a wall with an assignment and it's beginning to really frustrate me. Essentially I have a CSV file and my goal is to count how an the amount of times a string is called. So like column 1 would have a string and column 2 would have a integer connected to it. I ultimately need this to be formatted into a dictionary. Where I am stuck is how the heck do I do this without using imported libraries. I am only allowed to iterate through the file using for loops. Would my best bet be indexing each line and creating that into a string and count how many times that string is called? Any insight would be appreciated.
If you don't want to you any library (and assuming you are using python) you can use a dict comprehension, like this:
with open("data.csv") as file:
csv_as_dict = {line[0]: line[1] for line in file.readlines()}
Note: The question is possibly a duplicate of Creating a dictionary from a csv file?.
I'm using webwrite to post to an api. One of the field names in the json object I'm trying to setup for posting is odata.metadata. I'm making a struct that looks like this for the json object:
json = struct('odata.metadata', metadata, 'odata.type', type, 'Name', name,);
But I get an error
Error using struct
Invalid field name "odata.metadata"
Here's the json object I'm trying to use in Matlab. All strings for simplicity:
{
"odata.metadata": "https://website.com#Element",
"odata.type": "Blah.Blah.This.That",
"Name": "My Object"
}
Is there a way to submit this json object or is it a lost cause?
Field names are not allowed to have dots in them. The reason why is because this will be confused with accessing another nested structure within the structure itself.
For example, doing json.odata.metadata would be interpreted as json being a struct with a member whose field name is odata where odata has another member whose field name is metadata. This would not be interpreted as a member with the combined field name as odata.metadata. You're going to have to rename the field to something else or change the convention of your field name slightly.
Usually, the convention is to replace dots with underscores. An automated way to take care of this if you're not willing to manually rename the field names yourself is to use a function called matlab.lang.makeValidName that takes in a string and converts it into a valid field name. This function was introduced in R2014a. For older versions, it's called genvarname.
For example:
>> matlab.lang.makeValidName('odata.metadata')
ans =
odata_metadata
As such, either replace all dots with _ to ensure no ambiguities or use matlab.lang.makeValidName or genvarname to take care of this for you.
I would suggest using a a containers.Map instead of a struct to store your data, and then creating your JSON string by iterating over the Map filednames and appending them along with the data to your JSON.
Here's a quick demonstration of what I mean:
%// Prepare the Map and the Data:
metadata = 'https://website.com#Element';
type = 'Blah.Blah.This.That';
name = 'My Object';
example_map = containers.Map({'odata.metadata','odata.type','Name'},...
{metadata,type,name});
%// Convert to JSON:
JSONstr = '{'; %// Initialization
map_keys = keys(example_map);
map_vals = values(example_map);
for ind1 = 1:example_map.Count
JSONstr = [JSONstr '"' map_keys{ind1} '":"' map_vals{ind1} '",'];
end
JSONstr =[JSONstr(1:end-1) '}']; %// Finalization (get rid of the last ',' and close)
Which results in a valid JSON string.
Obviously if your values aren't strings you'll need to convert them using num2str etc.
Another alternative you might want to consider is the JSONlab FEX submission. I saw that its savejson.m is able to accept cell arrays - which can hold any string you like.
Other alternatives may include any of the numerous Java or python JSON libraries which you can call from MATLAB.
I probably shouldn't add this as an answer - but you can have '.' in a struct fieldname...
Before I go further - I do not advocate this and it will almost certainly cause bugs and a lot of trouble down the road... #rayryeng method is a better approach
If your struct is created by a mex function which creates a field that contains a "." -> then you will get what your after.
To create your own test see the Mathworks example and modify accordingly.
(I wont put the full code here to discourage the practice).
If you update the char example and compile to test_mex you get:
>> obj = test_mex
obj =
Doublestuff: [1x100 double]
odata.metadata: 'This is my char'
Note: You can only access your custom field in Matlab using dynamic fieldnames:
obj.('odata.metadata')
You need to use a mex capability to update it...
I was wondering if anyone knew why this return is backwards with CGI::Application::Plugin::JSON
sub {
my ($self) = #_;
my $q = $self->query;
return $self->json_body({ result => '1', message => 'I should be AFTER result'} );
}
The Output is as follows:
{"message":"I should be AFTER result","result":"1"}
I would assume it would format the JSON left to right from the key/value pairs, and remembering it will be backwards is okay, but I have alot of returns to handle and the validation on the client-side is done with the 'result' value so if I am just missing something I would like to have it output just like it is input.
EDIT:
Also I just notices it is not returning a JSON Boolean type object as "result":"1" will deserialize as as sting object and not a JSON Boolean. Is there a way to have it output "result":1
Thanks for any help I can get with this one.
I would assume it would format the JSON left to right from the key/value pairs
You're confusing the list you assigned to the hash with the hash itself. Hashes don't have a left and a right; they have an array of linked lists.
You're getting the order in which the elements are found in the hash. You can't control that order as long as you use a hash.
If you really do need to have the fields in a specific order (which would be really weird), you could try using something that looks like a hash but remembers insertion order (like Tie::IxHash).
remembering it will be backwards is okay
Not only are they not "backwards", the order isn't even predictable.
$ perl -MJSON -E'say encode_json {a=>1,b=>2,c=>3} for 1..3'
{"b":2,"c":3,"a":1}
{"c":3,"a":1,"b":2}
{"a":1,"c":3,"b":2}
Is there a way to have it output "result":1
result => 1
I'm trying to take a csv file and turn it into a dictionary, via csv.DictReader. After doing this, I want to modify one of the columns of the dictionary, and then write the data into a tsv file. I'm dealing with words and word frequencies in a text.
I've tried using the dict.value() function to obtain the dictionary values, but I get an error message saying "AttributeError: DictReader instance has no attribute "values""
Below is my code:
#calculate frequencies of each word in Jane Austen's "Pride and Prejudice"
import csv
#open file with words and counts for the book, and turn into dictionary
fob = open("P&P.csv", "r")
words = csv.DictReader(fob)
dict = words
#open a file to write the words and frequencies to
fob = open("AustenWords.tsv", "w")
#set total word count
wordcount = 120697
for row in words:
values = dict.values()
print values
Basically, I have the total count of each word in the text (i.e. "a","1937") and I want to find the percentage of the total word count that the word in question uses (thus, for "a", the percentage would be 1937/120697.) Right now my code doesn't have the equation for doing this, but I'm hoping, once I obtain the values of each row, to write a row to the new file with the word and the calculated percentage. If anyone has a better way (or any way!) to do this, I would greatly appreciate any input.
Thanks
To answer the basic question - "why am I getting this error" - when you call csv.DictReader(), the return type is an iterator not a Dictionary.
Each ROW in the iterator is a Dictionary which you can then use for your script:
for row in words:
values = row.values()
print values
Thank goodness for Matt Dunnam's answer (I'd reply to it but I don't see how to). csv.DictReader objects are, quite counter-intuitively, NOT dictionary objects (although I think I am beginning to see some usefulness in why not). As he says, csv.DictReader objects are an iterator (with my intro level to python, I think this is like a list maybe). Each entry in that object (which is not a dictionary) is a dictionary.
So, csv.DictReader returns something like a list of dictionaries, which is not the same as returning one dictionary object, despite the name.
What is nice, so far, is that csv.DictReader did preserve my key values in the first row, and placed them correctly in each of the many dictionary objects that are a part of the iterable object it actually returned (again, it does not return a dictionary object!).
I've wasted about an hour banging my head on this, the documentation is not clear enough, although now that I understand what type of object csv.DictReader returns, the documentation is a lot clearer. I think the documentation says something like how it returns an iterable object, but if you think it returns a dictionary and you don't know if dictionaries are iterable or not then this is easy to read as "returns a dictionary object".
The documentation should say "This does not return a dictionary object, but instead returns an iterable object containing a dictionary object for each entry" or some such thing. As a python newbie who hasn't coded in 20 years, I keep running into problems where the documentation is written by and for experts and it is too dense for beginners.
I'm glad it's there and that people have given their time to it, but it could be made easier for beginners while not reducing its worth to expert pythonistas.