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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).

Build a List of Tuples from a Dict

I have a list y of keys from a dictionary that is derived from a call to the Google Places API.
I would like to build a list of tuples for each point of interest:
lst = []
for i in range(len(y)):
lst.append((y[i]['name'], y[i]['formatted_address'], y[i]['opening_hours']['open_now'], y[i]['rating']))
This works if the field is in the list and I receive a list of results that look like the one below, which is exactly what I want:
("Friedman's", '1187 Amsterdam Ave, New York, NY 10027, USA', True, 4.2)
However, the script throws an error if a desired field is not in the list y. How can I build a list of tuples that checks whether the desired field is in y before building the tuple?
Here's what I've tried:
for i in range(len(y)):
t = ()
if y[i]['name']:
t = t + lst.append(y[i]['name'])
if y[i]['formatted_address']:
t = t + lst.append(y[i]['formatted_address'])
if y[i]['opening_hours']['open_now']:
t = t + lst.append(y[i]['opening_hours']['open_now'])
if y[i]['rating']:
t = t + lst.append(y[i]['rating'])
lst.append(t)
However, this doesn't work and seems very inelegant. Any suggestions?

This list comprehension uses default values when one of the keys is not present (using dict.get()). I added variables so you can set the desired default values.
default_name = ''
default_address = ''
default_open_now = False
default_rating = 0.0
new_list = [
(
e.get('name', default_name),
e.get('formatted_address', default_address),
e.get('opening_hours', {}).get('open_now', default_open_now),
e.get('rating', default_rating),
)
for e in y]

For a start, you should almost never loop over range(len(something)). Always iterate over the thing directly. That goes a long way to making your code less inelegant.
For the actual issue, you could loop over the keys and only add the item if it is in the dict. That gets a bit more complicated with your one element that is a nested lookup, but if you take it out then your code just becomes:
for item in y:
lst.append(tuple(item[key] for key in ('name', 'formatted_address', 'opening_hours', 'rating') if key in item))

You can use the get feature from dict.
y[i].get('name')
if y[i] has key 'name' returns the value or None. For nested dicts, use default value from get.
y[i].get('opening_hours', {}).get('open_now')
For data structure, I recommend to keep it as an dict, and add dicts to an list.
lst = []
lst.append({'name': "Friedman's", "address": '1187 Amsterdam Ave, New York, NY 10027, USA'})

Try this:
for i in y:
lst.append((v for k,v in i.items()))

you can use the keys method to find the keys in a dict. In your case:
lst=[]
fields = ('name', 'formatted_address', 'opening_hours' 'open_now', 'rating')
for i in range(len(y)):
data = []
for f in fields:
if f in y[].keys():
data.append(y[i][f])
else:
data.append(None)
lst.append(set(data))
note that you can also get all the key, value pairs in a dict using the items() method. That would actually simply the code a bit. To make it even better, itterate over the set, rather than calling len(set) to:
lst=[]
fields = ('name', 'formatted_address', 'opening_hours' 'open_now', 'rating')
for i in y:
data = []
for key, value in i.items():
if key in fields:
data.append(value)
else:
data.append(None)
lst.append(set(data))

create a new dict based on old dict

I am have the following dict:
abc = {"type":"insecure","id":"1","name":"peter"}
what I want to do is to have a new dict based on the old dict in which there is no key "type" and key "id" is changed to "identity". The new dict will look as follows:
xyz = {"identity":"1","name":"peter"}
The solution that I came up was as follows:
abc = {"type":"insecure","id":"1","name":"peter"}
xyz = {}
black_list_values = set(("type","id"))
for k in abc:
if k not in blacklist_values:
xyz[k] = abc[k]
xyz["identity"] = abc["id"]
I was wondering if its the fastest and efficient way to do that? Right now, "abc" have only three values. If "abc" is much bigger and have many values then is my solution still the efficient and fast.

You can use a dict-comprehension:
abc = {"type":"insecure","id":"1","name":"peter"}
black_list = {"type"}
rename ={"id":"identity"} #use a mapping dictionary in case you want to rename multiple items
dic = {rename.get(key,key) : val for key ,val in abc.items() if key not in black_list}
print dic
output:
{'name': 'peter', 'identity': '1'}

You want to create a new dictionary anyway. You can iterate over keys/values in a dict comprehension, which is more compact, but functionally the same:
abc = {"type":"insecure","id":"1","name":"peter"}
black_list_values = set(("type","id"))
xyz = {k:v for k,v in abc.iteritems() if k not in black_list_values}
xyz["identity"] = abc["id"]

Without iterating through the original dict:
abc = {"type":"insecure","id":"1","name":"peter"}
xyz = abc.copy()
xyz.pop('type')
xyz['identity'] = xyz.pop('id')

If all the keys are pre-known and it's a short list of keys, then the obvious solution is just
xyz = {"identity":abc["id"],"name":abc["name"]}

A another simple suggestion would be to use the dict() function:
abc = {"type":"insecure","id":"1","name":"peter"}
xyz = dict(abc)
Then perform the replacement in any way you see fit =-)

Python procedure to populate dictionary from data in 2 separate lists

I am trying to create an automated python procedure that uses two separate lists to create a dictionary and so far I am failing. I have two sorted lists where the nth item in the fist list corresponds to the nth item in the second list and I want to combine them into a dictionary.
For example, a subset of the 2 lists are as follows;
name = ['Adam', 'Alfred', 'Amy', 'Andy', 'Bob']
year = [1972, 1968, 1985, 1991, 1989]
I would want my output to be:
birth_years = {'Adam':1972, 'Alfred':1968, 'Amy':1985, 'Andy':1991, 'Bob':1989}
I was trying to do this with a for loop, but I could not get it to work. I appreciate any help.

Use the zip and dict functions to construct a dictionary out of a list of tuples:
birth_years = dict(zip(name, year))
And if you're curious, this would be how I would try to do it with a for loop:
birth_years = {}
for index, n in enumerate(name):
birth_years[n] = years[index]
I think I like the first example more.

birth_years = {}
for i in range(len(name)):
birth_years[name[i]] = year[i]

Try a dictionary comprehension:
birth_years = {nm:year[idx] for idx, nm in enumerate(name)}

Your lists would be better named names and years. You got off to a good start by trying to do it with a for loop. Most practical data processing problems involve error checking, which is just a tad difficult with one-liners. Example:
birth_years = {}
for i, name in enumerate(names):
if name in birth_years:
log_duplicate(i, name, years[i]))
else:
birth_years[name] = years[i]

Python, Lists - Use 'Item' as integer variable

Sorry for the poor title, basically I want to access a list item based on another list item:
catList = [john, james, jack]
dateList = [1y, 2y, 3m]
for item in catList:
if item in typeList[1]:
calendar += 1
if item in typeList[2]:
connector += 1
print dateList[item]
It's the last line that I want to achieve, essentially to print the value of dateList which corresponds to the value of catList.
Any ideas? Thanks
Edit: My catDict & dateDict are lists so they don't have keys, just values.

If the keys to catDict are numeric strings you can use print dateDict[int(item)]. Otherwise, I'm uncertain - we need to see what the declaration of catDict looks like.
If you're using lists you want to do this:
for idx, val in enumerate(catList):
print dateList[idx]