Develop Reference

What kind of data structure is this? Python

Studying Python, I am following an excellent Corey Schafer tutorial on Flask, he does this (I have extracted and summarized it for obvious reasons):
from folder_app import app # I did it to follow the structure and that the code is equal to the original
s = Serializer(app.config['SECRET_KEY'], 1800) # key, seconds
token = s.dumps({'user_id': 1}).decode('utf-8')
s = Serializer(app.config['SECRET_KEY'])
user_id = s.loads(token)['user_id'] # This is where I have the doubt
print(user_id)
print(type(s.loads(token)))
The code works, the problem I have is that although as you can see (s.loads (token)) is a dict, I expected to see something like this s.loads ({token ['user_id']}), or s.loads (token ['user_id']) or something like that. That is, it is a dict but it does not seem so. And my doubt goes in the sense if this comes from a greater concept of those they call "pythonic" (which I have not seen so far), or is something that only happens particularly as in this case. Incidentally, https://itsdangerous.palletsprojects.com/en/1.1.x/jws/ this appears: loads (self, s, salt = None, return_header = False) the arguments are in parentheses. I hope it is clear what my doubt is :)

I know this is not answer per say but just to add to my comment. This is an example of how the loads function works on dictionaries with the json module. https://docs.python.org/3/library/json.html#json.loads. What it does is take a json string and return the dictionary type object in Python. Your Serializer is doing something similar. It takes the token string and represents it as an object like dict
The s.dumps I am assuming is similar to json.dumps which gives you the json string representation of python dictionary.
import json
my_dict = json.loads('{"user_id": "Mane", "name": "Joe"}')
my_dict['user_id']
So you could just do json.loads('{"user_id": "Mane", "name": "Joe"}')['user_id'] which is just chaining the operations.

Scraping data from a http & javaScript site

I currently want to scrape some data from an amazon page and I'm kind of stuck.
For example, lets take this page.
https://www.amazon.com/NIKE-Hyperfre3sh-Athletic-Sneakers-Shoes/dp/B01KWIUHAM/ref=sr_1_1_sspa?ie=UTF8&qid=1546731934&sr=8-1-spons&keywords=nike+shoes&psc=1
I wanted to scrape every variant of shoe size and color. That data can be found opening the source code and searching for 'variationValues'.
There we can see sort of a dictionary containing all the sizes and colors and, below that, in 'asinToDimentionIndexMap', every product code with numbers indicating the variant from the variationValues 'dictionary'.
For example, in asinToDimentionIndexMap we can see
"B01KWIUH5M":[0,0]
Which means that the product code B01KWIUH5M is associated with the size '8M US' (position 0 in variationValues size_name section) and the color 'Teal' (same idea as before)
I want to scrape both the variationValues and the asinToDimentionIndexMap, so i can associate the IndexMap numbers to the variationValues one.
Another person in the site (thanks for the help btw) suggested doing it this way.
script = response.xpath('//script/text()').extract_frist()
import re
# capture everything between {}
data = re.findall(script, '(\{.+?\}_')
import json
d = json.loads(data[0])
d['products'][0]
I can sort of understand the first part. We get everything that's a 'script' as a string and then get everything between {}. The issue is what happens after that. My knowledge of json is not that great and reading some stuff about it didn't help that much.
Is it there a way to get, from that data, 2 dictionaries or lists with the variationValues and asinToDimentionIndexMap? (maybe using some regular expressions in the middle to get some data out of a big string). Or explain a little bit what happens with the json part.
Thanks for the help!
EDIT: Added photo of variationValues and asinToDimensionIndexMap

I think you are close Manuel!
The following code will turn your scraped source into easy-to-select boxes:
import json
d = json.loads(data[0])
JSON is a universal format for storing object information. In other words, it's designed to interpret string data into object data, regardless of the platform you are working with.
https://www.w3schools.com/js/js_json_intro.asp
I'm assuming where you may be finding things a challenge is if there are any errors when accessing a particular "box" inside you json object.
Your code format looks correct, but your access within "each box" may look different.
Eg. If your 'asinToDimentionIndexMap' object is nested within a smaller box in the larger 'products' object, then you might access it like this (after running the code above):
d['products'][0]['asinToDimentionIndexMap']
I've hacked and slash a little bit so you can better understand the structure of your particular json file. Take a look at the link below. On the right-hand side, you will see "which boxes are within one another" - which is precisely what you need to know for accessing what you need.
JSON Object Viewer
For example, the following would yield "companyCompliancePolicies_feature_div":
import json
d = json.loads(data[0])
d['updateDivLists']['full'][0]['divToUpdate']
The person helping you before outlined a general case for you, but you'll need to go in an look at structure this way to truly find what you're looking for.

variationValues = re.findall(r'variationValues\" : ({.*?})', ' '.join(script))[0]
asinVariationValues = re.findall(r'asinVariationValues\" : ({.*?}})', ' '.join(script))[0]
dimensionValuesData = re.findall(r'dimensionValuesData\" : (\[.*\])', ' '.join(script))[0]
asinToDimensionIndexMap = re.findall(r'asinToDimensionIndexMap\" : ({.*})', ' '.join(script))[0]
dimensionValuesDisplayData = re.findall(r'dimensionValuesDisplayData\" : ({.*})', ' '.join(script))[0]
Now you can easily convert them to json as use them combine as you wish.

json change dictionary item to a list with one dictionary

I'm working with a Rest Api for finding address details. I pass it an address and it passes back details for that address: lat/long, suburb etc. I'm using the requests library with the json() method on the response and adding the json response to a list to analyse later.
What I'm finding is that when there is a single match for an address the 'FoundAddress' key in the json response contains a dictionary but when more than one match is found the 'FoundAddress' key contains a list of dictionaries.
The returned json looks something like:
For a single match:
{
'FoundAddress': {AddressDetails...}
}
For multiple matches:
{
'FoundAddress': [{Address1Details...}, {Address2Details...}]
}
I don't want to write code to handle a single match and then multiple matches.
How can I modify the 'FoundAddress' so that when there is a single match it changes it to a list with a single dictionary entry? Such that I get something like this:
{
'FoundAddress': [{AddressDetails...}]
}

If it's the external API sending responses in that format then you can't really change FoundAddress itself, since it will always arrive in that format.
You can change the response if you want to, since you have full control over what you've received:
r = json.parse(response)
fixed = r['FoundAddress'] if (type(r['FoundAddress']) is list) else [r['FoundAddress']]
r['FoundAddress'] = fixed
Alternatively you can do the distinction at address usage time:
def func(foundAddress):
# work with a single dictionary instance here
then:
result = map(func, r['FoundAddress']) if (type(r['FoundAddress']) is list) else [func(r['FoundAddress'])]
But honestly I'd take a clear:
if type(r['FoundAddress']) is list:
result = map(func, r['FoundAddress'])
else:
result = func(r['FoundAddress'])
or the response fix-up over the a if b else c one-liner any day.

If you can, I would just change the API. If you can't there's nothing magical you can do. You just have to handle the special case. You could probably do this in one place in your code with a function like:
def handle_found_addresses(found_addresses):
if not isinstance(found_addresses, list):
found_addresses = [found_addreses]
...
and then proceed from there to do whatever you do with found addresses as if the value is always a list with one or more items.

How to read and assign variables from an API return that's formatted as Dictionary-List-Dictionary?

So I'm trying to learn Python here, and would appreciate any help you guys could give me. I've written a bit of code that asks one of my favorite websites for some information, and the api call returns an answer in a dictionary. In this dictionary is a list. In that list is a dictionary. This seems crazy to me, but hell, I'm a newbie.
I'm trying to assign the answers to variables, but always get various error messages depending on how I write my {},[], or (). Regardless, I can't get it to work. How do I read this return? Thanks in advance.
{
"answer":
[{"widgets":16,
"widgets_available":16,
"widgets_missing":7,
"widget_flatprice":"156",
"widget_averages":15,
"widget_cost":125,
"widget_profit":"31",
"widget":"90.59"}],
"result":true
}
Edited because I put in the wrong sample code.

You need to show your code, but the de-facto way of doing this is by using the requests module, like this:
import requests
url = 'http://www.example.com/api/v1/something'
r = requests.get(url)
data = r.json() # converts the returned json into a Python dictionary
for item in data['answer']:
print(item['widgets'])

Assuming that you are not using the requests library (see Burhan's answer), you would use the json module like so:
data = '{"answer":
[{"widgets":16,
"widgets_available":16,
"widgets_missing":7,
"widget_flatprice":"156",
"widget_averages":15,
"widget_cost":125,
"widget_profit":"31",
"widget":"90.59"}],
"result":true}'
import json
data = json.loads(data)
# Now you can use it as you wish
data['answer'] # and so on...

First I will mention that to access a dictionary value you need to use ["key"] and not {}. see here an Python dictionary syntax.
Here is a step by step walkthrough on how to build and access a similar data structure:
First create the main dictionary:
t1 = {"a":0, "b":1}
you can access each element by:
t1["a"] # it'll return a 0
Now lets add the internal list:
t1["a"] = ["x",7,3.14]
and access it using:
t1["a"][2] # it'll return 3.14
Now creating the internal dictionary:
t1["a"][2] = {'w1':7,'w2':8,'w3':9}
And access:
t1["a"][2]['w3'] # it'll return 9
Hope it helped you.

associative list python

i am parsing some html form with Beautiful soup. Basically i´ve around 60 input fields mostly radio buttons and checkboxes. So far this works with the following code:
from BeautifulSoup import BeautifulSoup
x = open('myfile.html','r').read()
out = open('outfile.csv','w')
soup = BeautifulSoup(x)
values = soup.findAll('input',checked="checked")
# echoes some output like ('name',1) and ('value',4)
for cell in values:
# the following line is my problem!
statement = cell.attrs[0][1] + ';' + cell.attrs[1][1] + ';\r'
out.write(statement)
out.close()
x.close()
As indicating in the code my problem ist where the attributes are selected, because the HTML template is ugly, mixing up the sequence of arguments that belong to a input field. I am interested in name="somenumber" value="someothernumber" . Unfortunately my attrs[1] approach does not work, since name and value do not occur in the same sequence in my html.
Is there any way to access the resulting BeautifulSoup list associatively?
Thx in advance for any suggestions!

My suggestion is to make values a dict. If soup.findAll returns a list of tuples as you seem to imply, then it's as simple as:
values = dict(soup.findAll('input',checked="checked"))
After that you can simply refer to the values by their attribute name, like what Peter said.
Of course, if soup.findAll doesn't return a list of tuples as you've implied, or if your problem is that the tuples themselves are being returned in some weird way (such that instead of ('name', 1) it would be (1, 'name')), then it could be a bit more complicated.
On the other hand, if soup.findAll returns one of a certain set of data types (dict or list of dicts, namedtuple or list of namedtuples), then you'll actually be better off because you won't have to do any conversion in the first place.
...Yeah, after checking the BeautifulSoup documentation, it seems that findAll returns an object that can be treated like a list of dicts, so you can just do as Peter says.
http://www.crummy.com/software/BeautifulSoup/documentation.html#The%20attributes%20of%20Tags
Oh yeah, if you want to enumerate through the attributes, just do something like this:
for cell in values:
for attribute in cell:
out.write(attribute + ';' + str(cell[attribute]) + ';\r')

I'm fairly sure you can use the attribute name like a key for a hash:
print cell['name']