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filtering python list/dictionary and retrieve value for selected key

working on Python script. I get a result that is list:
a = [{'S_RAF': {'C_C106': {'D_1103': 'AVE', 'D_1104': '3-AB3242'}}}, {'S_RAF': {'C_C106': {'D_1103': 'OI', 'D_1104': '31503302130'}}}, {'S_RAF': {'C_C106': {'D_1103': 'PQ', 'D_1104': 'IBAN3102495934895'}}}]
And I would like to get the value of Key: D_1104, when the value for key D_1103 is PQ.
what would be best way in python to get the value of this key in element S_RAF/C_C106/{D_1103=PQ}. function should return: IBAN3102495934895.
Thanks
I tried:
a[2]['C_C106']['D_1104']
but is not correct.

Should do it:
a[2]['S_RAF']['C_C106']['D_1104'] # IBAN3102495934895

You can iterate through the list and check the values in each dictionary like this:
for dictionary in a:
if dictionary['S_RAF']['C_C106']['D_1103'] == 'PQ':
iban = dictionary['S_RAF']['C_C106']['D_1104']

Get ISBNs where D_1103 == "PQ".
ibans = [x["S_RAF"]["C_C106"]["D_1104"] for x in a if x["S_RAF"]["C_C106"]["D_1103"]=="PQ"]
ibans = ibans[0] # "IBAN3102495934895"

Iterating over A dict to access a specific key value

I have a list of dicts ('sortings') that I am trying to iterate through to access a values in one specific key of each dict. My code keeps saying that there is a key error for the desired value in the dict. If I print inside the for loop, it prints with the values entered but once I exit the for loop it says there is a key error.
for i in range(sort_len):
sentence = sortings[i]['content']
containing_messages.append(sentence)
print(containing_messages)

This is an answer for my understanding of the question. I would require the given input and expected output to provide a better answer.
list_of_dicts = [{'keya':'value1_1','keyb':'value2_1','keyc':'value3_1'},
{'keya':'value1_2','keyb':'value2_2','keyc':'value3_2'},
{'keya':'value1_3','keyb':'value2_3','keyc':'value3_3'}]
list_of_key_values = [my_dict['keyb'] for my_dict in list_of_dicts]
print list_of_key_values

How to create a dictionary whose values are sets?

I'm working on an exercise that requires me to build two dictionaries, one whose keys are country names, and the values are the GDP. This part works fine.
The second dictionary is where I'm lost, as the keys are supposed to be the letters A‐Z and the values are sets of country names. I tried using a for loop, which I've commented on below, where the issue lies.
If the user enters a string with only one letter (like A), the program should print all the countries that begin with that letter. When you run the program, however, it only prints out one country for each letter.
The text file contains 228 lines. ie:
1:Qatar:98900
2:Liechtenstein:89400
3:Luxembourg:80600
4:Bermuda:69900
5:Singapore:59700
6:Jersey:57000
etc.
And here's my code.
initials = []
countries=[]
incomes=[]
dictionary={}
dictionary_2={}
keywordFile = open("raw.txt", "r")
for line in keywordFile:
line = line.upper()
line = line.strip("\n")
line = line.split(":")
initials.append(line[1][0]) # first letter of second element
countries.append(line[1])
incomes.append(line[2])
for i in range(0,len(countries)):
dictionary[countries[i]] = incomes[i]
this for loop should spit out 248 values (one for each country), where the key is the initial and the value is the country name. However, it only spits out 26 values (one country for each letter in the alphabet)
for i in range(0,len(countries)):
dictionary_2[initials[i]] = countries[i]
print(dictionary_2)
while True:
inputS = str(input('Enter an initial or a country name.'))
if inputS in dictionary:
value = dictionary.get(inputS, "")
print("The per capita income of {} is {}.".format((inputS.title()), value ))
elif inputS in dictionary_2:
value = dictionary_2.get(inputS)
print("The countries that begin with the letter {} are: {}.".format(inputS, (value.title())))
elif inputS.lower() in "quit":
break
else:
print("Does not exit.")
print("End of session.")
I'd appreciate any input leading me in the right direction.

Use defaultdict to make sure each value of your initials dict is a set, and then use the add method. If you just use = you'll be overwriting the initial keys value each time, defaultdict is an easier way of using an expression like:
if initial in dict:
dict[initial].add(country)
else:
dict[initial] = {country}
See the full working example below, and also note that i'm using enumerate instead of range(0,len(countries)), which i'd also recommend:
#!/usr/bin/env python3
from collections import defaultdict
initials, countries, incomes = [],[],[]
dict1 = {}
dict2 = defaultdict(set)
keywordFile = """
1:Qatar:98900
2:Liechtenstein:89400
3:Luxembourg:80600
4:Bermuda:69900
5:Singapore:59700
6:Jersey:57000
""".split("\n\n")
for line in keywordFile:
line = line.upper().strip("\n").split(":")
initials.append(line[1][0])
countries.append(line[1])
incomes.append(line[2])
for i,country in enumerate(countries):
dict1[country] = incomes[i]
dict2[initials[i]].add(country)
print(dict2["L"])
Result:
{'LUXEMBOURG', 'LIECHTENSTEIN'}
see: https://docs.python.org/3/library/collections.html#collections.defaultdict

The values for dictionary2 should be such that they can contain a list of countries. One option is to use a list as the values in your dictionary. In your code, you are overwriting the values for each key whenever a new country with the same initial is to be added as the value.
Moreover, you can use the setdefault method of the dictionary type. This code:
dictionary2 = {}
for country in countries:
dictionary2.setdefault(country[0], []).append(country)
should be enough to create the second dictionary elegantly.
setdefault, either returns the value for the key (in this case the key is set to the first letter of the country name) if it already exists, or inserts a new key (again, the first letter of the country) into the dictionary with a value that is an empty set [].
edit
if you want your values to be set (for faster lookup/membership test), you can use the following lines:
dictionary2 = {}
for country in countries:
dictionary2.setdefault(country[0], set()).add(country)

Here's a link to a live functioning version of the OP's code online.
The keys in Python dict objects are unique. There can only ever be one 'L' key a single dict. What happens in your code is that first the key/value pair 'L':'Liechtenstein' is inserted into dictionary_2. However, in a subsequent iteration of the for loop, 'L':'Liechtenstein' is overwritten by 'L':Luxembourg. This kind of overwriting is sometimes referred to as "clobbering".
Fix
One way to get the result that you seem to be after would be to rewrite that for loop:
for i in range(0,len(countries)):
dictionary_2[initials[i]] = dictionary_2.get(initials[i], set()) | {countries[i]}
print(dictionary_2)
Also, you have to rewrite the related elif statement beneath that:
elif inputS in dictionary_2:
titles = ', '.join([v.title() for v in dictionary_2[inputS]])
print("The countries that begin with the letter {} are: {}.".format(inputS, titles))
Explanation
Here's a complete explanation of the dictionary_2[initials[i]] = dictionary_2.get(initials[i], set()) | {countries[i]} line above:
dictionary_2.get(initials[i], set())
If initials[i] is a key in dictionary_2, this will return the associated value. If initials[i] is not in the dictionary, it will return the empty set set() instead.
{countries[i]}
This creates a new set with a single member in it, countries[i].
dictionary_2.get(initials[i], set()) | {countries[i]}
The | operator adds all of the members of two sets together and returns the result.
dictionary_2[initials[i]] = ...
The right hand side of the line either creates a new set, or adds to an existing one. This bit of code assigns that newly created/expanded set back to dictionary_2.
Notes
The above code sets the values of dictionary_2 as sets. If you want to use list values, use this version of the for loop instead:
for i in range(0,len(countries)):
dictionary_2[initials[i]] = dictionary_2.get(initials[i], []) + [countries[i]]
print(dictionary_2)

You're very close to what you're looking for, You could populate your dictionaries respectively while looping over the contents of the file raw.txt that you're reading. You can also read the contents of the file first and then perform the necessary operations to populate the dictionaries. You could achieve your requirement with nice oneliners in python using dict comprehensions and groupby. Here's an example:
country_per_capita_dict = {}
letter_countries_dict = {}
keywordFile = [line.strip() for line in open('raw.txt' ,'r').readlines()]
You now have a list of all lines in the keywordFile as follows:
['1:Qatar:98900', '2:Liechtenstein:89400', '3:Luxembourg:80600', '4:Bermuda:69900', '5:Singapore:59700', '6:Jersey:57000', '7:Libya:1000', '8:Sri Lanka:5000']
As you loop over the items, you can split(':') and use the [1] and [2] index values as required.
You could use dictionary comprehension as follows:
country_per_capita_dict = {entry.split(':')[1] : entry.split(':')[2] for entry in keywordFile}
Which results in:
{'Qatar': '98900', 'Libya': '1000', 'Singapore': '59700', 'Luxembourg': '80600', 'Liechtenstein': '89400', 'Bermuda': '69900', 'Jersey': '57000'}
Similarly using groupby from itertools you can obtain:
from itertools import groupby
country_list = country_per_capita_dict.keys()
country_list.sort()
letter_countries_dict = {k: list(g) for k,g in groupby(country_list, key=lambda x:x[0]) }
Which results in the required dictionary of initial : [list of countries]
{'Q': ['Qatar'], 'S': ['Singapore'], 'B': ['Bermuda'], 'L': ['Luxembourg', 'Liechtenstein'], 'J': ['Jersey']}
A complete example is as follows:
from itertools import groupby
country_per_capita_dict = {}
letter_countries_dict = {}
keywordFile = [line.strip() for line in open('raw.txt' ,'r').readlines()]
country_per_capita_dict = {entry.split(':')[1] : entry.split(':')[2] for entry in keywordFile}
country_list = country_per_capita_dict.keys()
country_list.sort()
letter_countries_dict = {k: list(g) for k,g in groupby(country_list, key=lambda x:x[0]) }
print (country_per_capita_dict)
print (letter_countries_dict)
Explanation:
The line:
country_per_capita_dict = {entry.split(':')[1] : entry.split(':')[2] for entry in keywordFile}
loops over the following list
['1:Qatar:98900', '2:Liechtenstein:89400', '3:Luxembourg:80600', '4:Bermuda:69900', '5:Singapore:59700', '6:Jersey:57000', '7:Libya:1000', '8:Sri Lanka:5000'] and splits each entry in the list by :
It then takes the value at index [1] and [2] which are the country names and the per capita value and makes them into a dictionary.
country_list = country_per_capita_dict.keys()
country_list.sort()
This line, extracts the name of all the countries from the dictionary created before into a list and sorts them alphabetically for groupby to work correctly.
letter_countries_dict = {k: list(g) for k,g in groupby(country_list, key=lambda x:x[0]) }
This lambda expression takes the input as the list of countries and groups together the names of countries where each x starts with x[0] into list(g).

How do I put values in an external files in size order using python?

I am trying to create a leader board for a quiz that I am creating. I have wrote the code to write the users name and their score in an external file, and they are currently in the order of which they were sent there, like so:
Ethan, 15
James, 20
Daniel, 7
I want to put them into size order so they look like so:
James, 20
Ethan, 15
Daniel, 7
I have spent quite while trying to figure it out but I am having a lot of trouble. I would really appreciate it if someone could help.
This is the code I am using to send the data to an external file:
file = open("Scores.txt","a")
file.write(supplied_Username)
file.write(",")
file.write(str(score))
file.write("\n")
file.close()

instead of using string to store username and score, use dict() to store it as key/value pair,
First let's create a dictionary,
data = {"Ethan":15,
"James":20,
"Daniel":7}
Now use sorted() function to sort items of dictionary, you can get dictionary items using dict.items(). dict.items() gives you list of tuple in this format, [('Ethan', 15), ('James', 20)]. This list of tuple has name on index 0, and score on index 1, hence we need to sort it on index 1. You can use lambda for provide key you want to use for sorting.
Finally use reverse = True because default behavior of sorted() is to sort in ascending order,
data_sorted = sorted(data.items(), key= lambda x:x[1], reverse=True)
Now open a file and write to it.
with open("d:/scores.txt","a") as score_file:
for k,v in data_sorted:
score_file.write("{}, {}\n".format(k, v))
Quick summary of what is happening above.
Create a dictionary to store your data.
use data.items() to get data out of dictionary in form of list of tuple.
use sorted() function to sort this list of tuple on index 1.
use reverse = True for descending order.
use with open to open a file and write sorted data to it.
Complete code,
data = {"Ethan": 15,"James": 20}
data_sorted = sorted(data.items(), key=lambda x: x[1], reverse=True)
with open("d:/scores.txt", "a") as score_file:
for k, v in data_sorted:
score_file.write("{}, {}\n".format(k, v))
It will write to a file scores.txt in d:/ drive (windows).

Maybe consider to create a dictionary and then you can sort of 'sort' the dictionary.
Here is a link with an example:
How to sort python dictionary by keys
Example code is:
keylist = mydict.keys()
keylist.sort()
for key in keylist:
print "%s: %s" % (key, mydict[key])
Otherwise, there is also the function 'sorted' which sorts however the key, so in your case the names.
Lastly, there is a good website from python.org:
How To: sorting

If you're storing people and their scores in a dictionary, you can create a list of tuples from the dictionary that is sorted.
import operator
people = {'Jamie': 20, 'Ethan': 15, 'Daniel': 7, 'Ronald': 25, 'Jeff': 0}
sortedPeople = sorted(people.items(), key=operator.itemgetter(1))
If you want to then write to a file, you just need to loop through the sorted list and write each value in the list.
Here is an example of how to get a list of people containing their name and their score.
people = {}
with open('file.txt', 'r') as f:
for line in f:
splitLine = (line.replace(',','')).split()
people[splitLine[0]] = splitLine[1]
Each splitLine is a list of size 2, the first element is the name, the second is the score. You can then add to your blank dictionary by stating that the first element (the name) is the value and the second element (the number) is the key.

Python dictionary check if the values match with other key values

I have created a python dictionary with a structure like :-
mydict = {'2018-08' : [32124,4234,23,2323,32423,342342],
'2018-07' : [13123,23424,2,3,4343,4232,2342],
'2018-06' : [1231,12,12313,12331,3123131313,434546,232]}
I want to check if any value in the values of key '2018-08' match with any values of other keys. is there a short way to write this?

You can simply loop over your expected values of mydict, and then for each of them check if its present in any of the values of the dictionary
You can use the idiom if item in list to check if item item is present in the list list
expected_values = mydict['2018-08']
found = False
for expected in expected_values:
for key in mydict:
if expected in mydict[key]:
found = True
break
Take into account that is a brute force algorithm and it may not be the optimal solution for larger dictionaries

The question is vague, so I am assuming that you want the values in the target month (e.g. 2018-08) that are contained somewhere within the other months.
Sets are much faster for testing membership compared to list iteration.
target = '2018-08'
s = set()
for k, v in mydict.iteritems():
if k != target:
s.update(v)
matches = set(mydict[target]) & s

Can use itertools.chain to create a long list
import itertools
for key,value in mydict.items():
temp_dict = mydict.copy()
temp_dict.pop(key)
big_value_list=list(itertools.chain(*temp_dict.values()))
print(key, set(value) & set(big_value_list))
Dry run by changing your provided inputs
mydict = {'2018-08' : [32124,4234,23,2323,32423,342342],
'2018-07' : [13123,23424,2,3,4343,4232,2342],
'2018-06' : [1231,12,12313,12331,3123131313,434546,232,342342,2342]}
Output:
('2018-08', set([342342]))
('2018-07', set([2342]))
('2018-06', set([342342, 2342]))