Develop Reference

Extracting Strings From a List

Hi I'm fairly new to Python and needed help with extracting strings from a list. I am using Python on Visual Studios.
I have hundreds of similar strings and I need to extract specific information so I can add it to a table in columns - the aim is to automate this task using python. I would like to extract the data between the headers 'Names', 'Ages' and 'Jobs'. The issue I am facing is that the number of entries of names, ages and jobs varies a lot within all the lists and so I would like to write unique code which could apply to all the lists.
list_x = ['Names','Ashley','Lee','Poonam','Ages', '25', '35', '42' 'Jobs', 'Doctor', 'Teacher', 'Nurse']
I am struggling to extract
['Ashley', 'Lee', 'Poonam']
I have tried the following:
for x in list_x:
if x == 'Names':
for y in list_x:
if y == 'Ages':
print(list_x[x:y])
This however comes up with the following error:
"Exception has occurred: typeError X
slice indices must be integers or None or have an index method"
Is there a way of doing this without specifying exact indices?

As the comment suggested editing the data is the easiest way to go, but if you have to...
newList = oldList[oldList.index('Names') + 1:oldList.index("Ages")]
It just finds the indices of "Names" and "Ages" in the list, and extracts the bit between.
Lots can (and will) go wrong with this method though - if there's a name which is "Names", or if they are misspelt, etc.

For completeness sake, it might be not a bad idea to use an approach similar to the below.
First, build a list of indices of each of the desired headers:
list_x = ['Names', 'Ashley', 'Lee', 'Poonam', 'Ages', '25', '35', '42', 'Jobs', 'Doctor', 'Teacher', 'Nurse']
headers = ('Names', 'Ages', 'Jobs')
header_indices = [list_x.index(header) for header in headers]
print('indices:', header_indices) # [0, 4, 8]
Then, create a list of values for each header, which we can infer from the positions where each header shows up in the list:
values = {}
for i in range(len(header_indices)):
header = headers[i]
start = header_indices[i] + 1
try:
values[header] = list_x[start:header_indices[i + 1]]
except IndexError:
values[header] = list_x[start:]
And finally, we can display it for debugging purposes:
print('values:', values)
# {'Names': ['Ashley', 'Lee', 'Poonam'], 'Ages': ['25', '35', '42'], 'Jobs': ['Doctor', 'Teacher', 'Nurse']}
assert values['Names'] == ['Ashley', 'Lee', 'Poonam']
For better time complexity O(N), we can alternatively use an approach like below so that we only have one for loop over the list to build a dict object with the values:
from collections import defaultdict
values = defaultdict(list)
header_idx = -1
for x in list_x:
if x in headers:
header_idx += 1
else:
values[headers[header_idx]].append(x)
print('values:', values)
# defaultdict(<class 'list'>, {'Names': ['Ashley', 'Lee', 'Poonam'], 'Ages': ['25', '35', '42'], 'Jobs': ['Doctor', 'Teacher', 'Nurse']})

Search lists inside dictionaries from API request

I'm trying to query a dictionary with a list and another dictionary inside. I'm using the deck of cards API and want to pull the value out.
drawCard='https://deckofcardsapi.com/api/deck/vx58tedq5moe/draw/?count=1'
response = requests.get(drawCard)
getValue = json.loads(response.text)
value= (getValue['cards'])
print (getValue)
print("")
print("")
print (value)
card= (getValue['cards'](''))
This is what I get when I print getValue.
{'deck_id': 'vx58tedq5moe', 'success': True, 'cards': [{'suit': 'SPADES', 'code': '0S', 'value': '10', 'images': {'png': 'https://deckofcardsapi.com/static/img/0S.png', 'svg': 'https://deckofcardsapi.com/static/img/0S.svg'}, 'image': 'https://deckofcardsapi.com/static/img/0S.png'}], 'remaining': 44}
I narrowed it down to this using getValue['cards'] but cant go any further.
[{'suit': 'SPADES', 'code': '0S', 'value': '10', 'images': {'png': 'https://deckofcardsapi.com/static/img/0S.png', 'svg': 'https://deckofcardsapi.com/static/img/0S.svg'}, 'image': 'https://deckofcardsapi.com/static/img/0S.png'}]
I want to grab the 10 from value

The value of getValue['cards'] is a list, so first you want to access the list element, getValue['cards'][0] then you can access the element 'value' with
getValue['cards'][0]['value']
If you want to get all value from all cards in the list of cards, you can use list comprehension to do something like
[c['value'] for c in getValue['cards']]

You go multiple levels down like this:
value= (getValue['cards']['value'])
BC 'cards' is the key to the list and 'value' is key to the value in the list witch have the value of 10.

searching for distinct dict in a list

With the following list of dict:
[ {'isn': '1', 'fid': '4', 'val': '1', 'ptm': '05/08/2019 14:22:39', 'sn': '111111' 'procesado': '0'},
{'isn': '1', 'fid': '4', 'val': '0', 'ptm': '05/08/2019 13:22:39', 'sn': '111111', 'procesado': '0'},
<...> ]
I would need to compare for each dict of the list if there are other element with:
equal fid
equal sn
distinct val (if val(elemX)=0 then val(elemY)=1)
distinct ptm (if val=0 of elemX then ptm of elemX < ptm of elemY)
This could be done in a traditional way using an external for loop an internal while, but this is not the optimal way to do it.
Trying to find a way to do that, I tried with something like this:
for p in lista:
print([item for item in lista if ((item["sn"] == p["sn"]) & (item["val"] == 0) & (p["val"] == 1) & (
datetime.strptime(item["ptm"], '%d/%m/%Y %H:%M:%S') < datetime.strptime(p["ptm"],'%d/%m/%Y %H:%M:%S')))])
But this does not work (and also is not optimal)

Just build a mapping from (fid,sn,val) onto a list of candidates (the whole dict, its index, or just its ptm (shown below), depending on what output you need). Also check whether any of its opposite numbers (under (fid,sn,!val)) are already present and do the ptm comparison if so:
seen={}
for d in dd:
f=d['fid']; s=d['sn']; v=int(d['val'])
p=datetime.strptime(d['ptm'],'%d/%m/%Y %H:%M:%S')
for p0 in seen.get((f,s,not v),()):
if p0!=p and (p0<p)==v: …
seen.setdefault((f,s,v),[]).append(p)
If you have a large number of values with the same key, you could use a tree to hasten the ptm comparisons, but that seems unlikely here. Using real data types for the individual values, and perhaps a namedtuple to contain them, would of course make this a lot nicer.

Python efficiently getting a specific value from a list of dictionaries

I am using an API to get results from a database that is returned in JSON format. I'm then trying to just extract certain keys/values and append them to a blank list. The field I want is eissn and the API returns results like this:
[
{'type': 'doi', 'id': '10.16472/j.chinatobacco.2017.045'},
{'type': 'pissn', 'id': '1004-5708'},
{'type': 'eissn', 'id': '1004-5708'}
]
I want to extract the eissn id which i have tried using this code:
deissnlist = []
for i in range(0,lengthD):
deissnlist.append(doajresult[i]['bibjson']['identifier'][3]
['id'])
Where lengthD/i are the number of results returned from the API. The problem is that the eissn ID is not always the 3rd dictionary in the list. Is there any way I can search the tuples and only get the eissn ID without using another for loop (and thus going from O(n) to O(n^2)? The expected output is just the single value of the eissn id (in this case 1004-5708)
I tried converting the list to a dictionary but that didn't work because it treated each tuple as it's own dictionary. Thanks!

I may have misunderstood question and over simplified; but, if you are looking to simply extract a list of the ids from that sample input, this is how I would do it:
input = [
{'type': 'doi', 'id': '10.16472/j.chinatobacco.2017.045'},
{'type': 'pissn', 'id': '1004-5708'},
{'type': 'eissn', 'id': '1004-5708'}
]
result = [x.get('id') for x in input]
print(result)
['10.16472/j.chinatobacco.2017.045', '1004-5708', '1004-5708']
Or for just the ids where type is eissn:
result = [x.get('id') for x in input if x.get('type') == 'eissn']

How do I turn list values into an array with an index that matches the other dic values?

Hoping someone can help me out. I've spent the past couple hours trying to solve this, and fair warning, I'm still fairly new to python.
This is a repost of a question I recently deleted. I've misinterpreted my code in the last example.The correct example is:
I have a dictionary, with a list that looks similar to:
dic = [
{
'name': 'john',
'items': ['pants_1', 'shirt_2','socks_3']
},
{
'name': 'bob',
items: ['jacket_1', 'hat_1']
}
]
I'm using .append for both 'name', and 'items', which adds the dic values into two new lists:
for x in dic:
dic_name.append(dic['name'])
dic_items.append(dic['items'])
I need to split the item value using '_' as the delimiter, so I've also split the values by doing:
name, items = [i if i is None else i.split('_')[0] for i in dic_name],
[if i is None else i.split('_')[0] for i in chain(*dic_items)])
None is used in case there is no value. This provides me with a new list for name, items, with the delimiter used. Disregard the fact that I used '_' split for names in this example.
When I use this, the index for name, and item no longer match. Do i need to create the listed items in an array to match the name index, and if so, how?
Ideally, I want name[0] (which is john), to also match items[0] (as an array of the items in the list, so pants, shirt, socks). This way when I refer to index 0 for name, it also grabs all the values for items as index 0. The same thing regarding the index used for bob [1], which should match his items with the same index.
#avinash-raj, thanks for your patience, as I've had to update my question to reflect more closely to the code I'm working with.

I'm reading a little bit between the lines but are you trying to just collapse the list and get rid of the field names, e.g.:
>>> dic = [{'name': 'john', 'items':['pants_1','shirt_2','socks_3']},
{'name': 'bob', 'items':['jacket_1','hat_1']}]
>>> data = {d['name']: dict(i.split('_') for i in d['items']) for d in dic}
>>> data
{'bob': {'hat': '1', 'jacket': '1'},
'john': {'pants': '1', 'shirt': '2', 'socks': '3'}}
Now the data is directly related vs. indirectly related via a common index into 2 lists. If you want the dictionary split out you can always
>>> dic_name, dic_items = zip(*data.items())
>>> dic_name
('bob', 'john')
>>> dic_items
({'hat': '1', 'jacket': '1'}, {'pants': '1', 'shirt': '2', 'socks': '3'})

You need a list of dictionaries because the duplicate keys name and items are overwritten:
items = [[i.split('_')[0] for i in d['items']] for d in your_list]
names = [d['name'] for d in your_list] # then grab names from list
Alternatively, you can do this in one line with the built-in zip method and generators, like so:
names, items = zip(*((i['name'], [j.split('_')[0] for j in i['items']]) for i in dic))

From Looping Techniques in the Tutorial.
for name, items in div.items():
names.append(name)
items.append(item)
That will work if your dict is structured
{'name':[item1]}

In the loop body of
for x in dic:
dic_name.append(dic['name'])
dic_items.append(dic['items'])
you'll probably want to access x (to which the items in dic will be assigned in turn) rather than dic.