Create dictionary from values found in two other dictionaries - python-3.x

Issue: I want to compare the two dictionaries - alist & blist - and use the values to create a new dictionary (clist).
****Please note that the alist is a result of comparing two other dicts****
The final solution would be:
clist = {'actual_url': ['bizname', 'buyer', 'date', 'Amount']
my attempt at doing this is below
Thanks for your help as I am really stuck!
alist = {acct_number': ['file_no', 'url', 'user', ['Biz_name', 'tool', 'date', 'amt']]}
blist = {acct_number: ['actual_case', 'actual_url']}
clist={}
for k, v in alist.item():
for k, v in blist.item():
if v==v:
clist[v]:alist[v]
print(clist)

If the 'actual_url' is always the second item in the list, you can do this:
clist = {}
clist[blist['acct_number'][1]] = alist['acct_number']
To iterate over multiple items in alist:
alist = {
'12345': ['2', 'my_url.com', 'James', ['James corp', 'a', '100', '30']],
'35299': ['5', 'another_url.org', 'Carrie', ['Carrie corp', 'b', '60', '20']],
}
blist = {
'12345': ['actual_case', 'my_url.com'],
'35299': ['actual_case', 'another_url.org'],
}
clist = {}
for acct_number, value in alist.items():
clist[blist[acct_number][1]] = value

Related

How to get unique values in nested list along single column?

I need to extract only unique sublists based on first element from a nested list. For e.g.
in = [['a','b'], ['a','d'], ['e','f'], ['g','h'], ['e','i']]
out = [['a','b'], ['e','f'], ['g','h']]
My method is two break list into two lists and check for elements individually.
lis = [['a','b'], ['a','d'], ['e','f'], ['g','h']]
lisa = []
lisb = []
for i in lis:
if i[0] not in lisa:
lisa.append(i[0])
lisb.append(i[1])
out = []
for i in range(len(lisa)):
temp = [lisa[i],lisb[i]]
out.append(temp)
This is an expensive operation when dealing with list with 10,00,000+ sublists. Is there a better method?
Use memory-efficient generator function with an auziliary set object to filter items on the first unique subelement (take first unique):
def gen_take_first(s):
seen = set()
for sub_l in s:
if sub_l[0] not in seen:
seen.add(sub_l[0])
yield sub_l
inp = [['a','b'], ['a','d'], ['e','f'], ['g','h'], ['e','i']]
out = list(gen_take_first(inp))
print(out)
[['a', 'b'], ['e', 'f'], ['g', 'h']]

convert list of dictionary values in to list of values

Hi all below is my list of dictionary
a=[{'Name': 'dhaya', 'Place': 'pune', 'Designation': 'fleetEngineer'},
{'Name': 'rishi', 'Place': 'maharastra', 'Designation': 'Sr.Manager'}]
iam expecting output like this
a={"Name":["dhaya","rishi],"Place":["pune","maharastra"],Designation:["fleetEngineer","Sr.Manager"]
"}
can any one assist
new_dict is the answer to the question you posted. Its the smallest and simplest.
b = list(a[0].keys())
new_dict = {}
for x in b:
new_dict[x] = [l[x] for l in a]
print('My expected dictionary',new_dict)
One can use nested for loops for this:
inputList = [{'Name': 'dhaya', 'Place': 'pune', 'Designation': 'fleetEngineer'}, {
'Name': 'rishi', 'Place': 'maharastra', 'Designation': 'Sr.Manager'}]
outputDict = {}
for origDict in inputList:
for key, val in origDict.items():
if key in outputDict:
outputDict[key].append(val)
else:
outputDict[key] = [val]
print(outputDict)
a=[{'Name': 'dhaya', 'Place': 'pune', 'Designation': 'fleetEngineer'}, {'Name': 'rishi', 'Place': 'maharastra', 'Designation': 'Sr.Manager'}]
Name = []
Place = []
Designation = []
for ele in a:
Name.append(ele["Name"])
Place.append(ele["Place"])
Designation.append(ele["Designation"])
new_a = {}
new_a['Name'] = Name
new_a['Place'] = Place
new_a["pune"] = Designation
print(new_a)

The problem of using {}.fromkey(['k1','k2'],[]) and {'k1':[],'k2':[]}

list1 = [99,55]
dict1 = {'k1':[],'k2':[]}
for num in list1:
if num > 77:
dict1['k1'].append(num)
else:
dict1['k2'].append(num)
print(dict1)
{'k1':[99],'k2':[55]}
But when I replaced dict1 = {'k1':[],'k2':[]} to {}.fromkeys(['k1','k2'],[]) , the result became {'k1': [99, 55], 'k2': [99, 55]}
why this happens? I really have no idea.
This happens because you are passing the same list object to both keys. This is the same situation as when you create an alias for a variable:
a = []
b = a
a.append(55)
b.append(99)
print(b)
prints [55, 99] because it is the same list instance.
If you want to make it more concise from a list of keys to initialize with empty list, you can do this:
dict1 = {k: [] for k in ('k1', 'k2')}
This will create a new list instance for every key.
Alternatively, you can use defaultdict
from collections import defaultdict
list1 = [99,55]
dict1 = defaultdict(list)
for num in list1:
if num > 77:
dict1['k1'].append(num)
else:
dict1['k2'].append(num)
print(dict1)
Also works.
The fromKeys() can also be supplied with a mutable object as the default value.
if we append value in the original list, the append takes place in all the values of keys.
example:
list1 = ['a', 'b', 'c', 'd']
list2 = ['SALIO']
dict1 = dict.fromkeys(list1, list2)
print(dict1)
output:
{'a': ['SALIO'], 'b': ['SALIO'], 'c': ['SALIO'], 'd': ['SALIO']}
then you can use this:
list1 = ['k1', 'k2']
dict1 = {'k1':[],'k2':[]}
list2 =[99,55]
for num in list2:
if num > 77:
a = ['k1']
dict1 = dict.fromkeys(a, [num])
else:
b = ['k2']
dict2 = dict.fromkeys(b,[num] )
res = {**dict1, **dict2}
print(res)
output:
{'k1': [99], 'k2': [55]}
You can also use the python code to merge dict code:
this function:
def Merge(dict1, dict2):
return(dict2.update(dict1))
then:
print(Merge(dict1, dict2)) #This return None
print(dict2) # changes made in dict2

Create a list of maps from multiple lists

Given three lists:
l1 = ['Alice', 'Bob', 'Jane']
l2 = ['30', '40', '50']
l3 = ['NY', 'Berlin', 'Stockholm']
how do I create something like this:
[['name': 'Alice', 'age': '30', 'city': 'NY'],
['name': 'Bob', 'age': '40', 'city': 'Berlin'],
['name': 'Jane', 'age': '50', 'city': 'Stockholm']]
I've tried [l1,l2,l3].transpose() but it returns list of lists and I can't figure out how to add proper keys to collectEntries()
Thanks
Edit:
Not-so-elegant solution I came up with is this:
assert l1.length == l2.length
assert l2.length == l3.length
def mapping = []
l1.eachWithIndex {name, index ->
def obj = [:]
obj.name = name
obj.age = l2[index]
obj.city = l3[index]
mapping += obj
obj = []
};
But there must be a better way, right?
An attempt at solving this more elegantly.
The following code:
def l1 = ['Alice', 'Bob', 'Jane']
def l2 = ['30', '40', '50']
def l3 = ['NY', 'Berlin', 'Stockholm']
def result = [l1, l2, l3].transpose().collect { a, b, c ->
[name: a, age: b, city: c]
}
println result
when run, prints out:
~> groovy solution.groovy
[[name:Alice, age:30, city:NY],
[name:Bob, age:40, city:Berlin],
[name:Jane, age:50, city:Stockholm]]
~>
(formatting added for readability).
The trick here is the transpose method which the question already mentions - [l1, l2, l3].transpose() returns:
[[Alice, 30, NY], [Bob, 40, Berlin], [Jane, 50, Stockholm]]
and the collect { a, b, c -> expression uses groovy destructuring to assign [Alice, 30, NY] to a, b, c etc. This is essentially the same mechanics that make it possible to write:
def (a, b, c) = [1, 2, 3]
for multiple assignments.
collectEntries returns a map and since you want a list on the outermost level it's not really the right tool here.

creating a dict based on two python dicts

I have two python dicts:
payload = {"key1":{"a":"1"},"key2":{"b":"2","c":"3"}}
and
data = {"1":"John","2":"Jacob"}
I would like my output to be:
{"key1":{"a":"John"},"key2":{"b":"Jacob","c":""}}
Any method that I try correctly prints the values, but does not update the output dictionary.
You can do something like this using dict comprehension :
payload = {"key1":{"a":"1"},"key2":{"b":"2","c":"3"}}
data = {"1":"John","2":"Jacob"}
final = {k: {i:data[j] if j in data.keys() else "" for i, j in payload[k].items()} for k in payload}
print(final)
Output:
{'key2': {'b': 'Jacob', 'c': ''}, 'key1': {'a': 'John'}}
There is no single method for this I am aware of, but you can use:
for k, v in payload.viewitems():
payload[k] = {}
for kv, vv in v.viewitems():
payload[k][kv] = data.get(vv, "")
if you then inspect payload it has the contents you are after:
{'key2': {'c': '', 'b': 'Jacob'}, 'key1': {'a': 'John'}}

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