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Complicated list comprehension [duplicate]

This question already has answers here:
Check if a given key already exists in a dictionary
(16 answers)
Closed 6 months ago.
Im trying to build a list through list comprehension in python.
What I have so far, and it works:
modified_list = [
{id: metadata}
for id, metadata in new_resource_map.items()
if id not in old_resource_map or metadata["lastModified"] != old_resource_map[id]["lastModified"]
]
My list called: modified_list
Every item in it is dictionary {id: metadata}
I want to add one more thing and it will look like that:
modified_list = [
{id: metadata}
for id, metadata in new_resource_map.items()
if id not in old_resource_map or metadata["lastModified"] != old_resource_map[id]["lastModified"] **or
metadata["infer_tags"] != old_resource_map[id]["infer_tags"]**
]
The problem is what the last part:
or metadata["infer_tags"] != old_resource_map[id]["infer_tags"]
The problem is not all of the files have that field ("infer_tags").
I wanna do this last thing only after I check if this field is existing.
Is anyone know to do that?

as Mechanic Pig suggests:
if id not in old_resource_map or metadata["lastModified"] != old_resource_map[id]["lastModified"] or
metadata.get("infer_tags", np.nan) != old_resource_map[id].get("infer_tags", np.nan)
Note that the default values used in the get() calls must not be valid values for infer_tags fields for this to be reliable.

Create Variable Name When Defining A Function [duplicate]

This question already has answers here:
How do I create variable variables?
(17 answers)
Closed 1 year ago.
I am working in Python trying to write a function using a list of variables.
Here is the data I am working with:
material_list=['leather', 'canvas', 'nylon']
def materialz(MAT):
MAT=support.loc[(material==MAT)].sum()
for i in enumerate(material_list):
materialz(i)
What I am looking for is to pass in each of the items in the list to the function to produce global variables.
leather=
canvas=
nylon=
Any help would be appreciated!

You could create a dictionary and dynamically assign the key-value pairs there. Such as:
material_list=['leather', 'canvas', 'nylon']
material_dict={}
for i in enumerate(material_list):
material_dict[i]=value #Where i would be the key and value the value in the key-value pair

you can use exec
var = 'hello'
output = hello
exec('var = "world"')
print(var)
output = world

python how to sort a variable like {'a b': c, 'd e':f ....} [duplicate]

This question already has answers here:
How do I sort a dictionary by value?
(34 answers)
Closed 2 years ago.
I have a variable.
Score = {}
After some calculation, the value of Score is :
{
'449 22876': 0.7491997,
'3655 6388': 0.99840045,
'2530 14648': 0.9219989,
'19957 832': 0.9806836,
'2741 23293': 0.64072967,
'22324 7525': 0.986661,
'9090 3811': 0.90206504,
'10588 5352': 0.8018138,
'18231 7515': 0.9991332,
'17807 14648': 0.9131582
.....
}
I want to sort it by the third value(e.g. 0.7491997).
I only want to get the top 100 high score.
How can I do?

if you want to sort the dictionary by the values of the dictionary (which is what I am getting from your question) you could do it with this lambda function:
sorted_dict = sorted(score.items(), key=lambda x: x[1])

How to get a random element from a python dictionary? [duplicate]

This question already has answers here:
How to get a random value from dictionary?
(19 answers)
Closed 3 years ago.
I want to get a value "element":"value" from a dictionary in python.
import random
country = {
"Spain":"Madrid",
"UK":"London",
"France":"Paris"
}
random.choice(country)
It returns me the following :
File "C:\Users\${username}\AppData\Local\Programs\Python\Python37-32\lib\random.py", line 262, in choice
return seq[i]
KeyError: 10
My aim, is to select a random value and be left with 1 Country - City left in the dictionary.
This does not answer my question : How to get a random value from dictionary in python

You can use the items method to get the pairs, then transform it to a list that supports indexing:
random.choice(list(country.items()))

i think you can implement in following way
import random
country = {
"Spain":"Madrid",
"UK":"London",
"France":"Paris"
}
keys = list(country.keys())
random_key = keys[random.randint(0, len(keys)-1)]
print(country[random_key])

You can make a random.choice from the keys() of the dict for instance.
You could print the values or make a new dict with just that entry:
import random
country = {
"Spain":"Madrid",
"UK":"London",
"France":"Paris"
}
k = random.choice(list(country.keys()))
print(k, country[k])
print({k:country[k]})

First of all, there's no order in a dictionary. The only list can be used for random.sample.
So change your code to random.choice(list(country.items()))

Call Dictionary With Randomly Chosen Value as Name - TypeError [duplicate]

This question already has answers here:
Access to value of variable with dynamic name
(3 answers)
Closed 6 years ago.
I am using a function that assigns a variable to equal the value of a randomly chosen key. Here the type is string and print works.
def explore():
import random
random_key = random.choice(explore_items.keys())
found_item = explore_items[random_key]
print type(found_item)
print found_item
Then, I want to use the variable name 'found_item' to call a dictionary of the same name, eg:
print found_item['key_1']
But I get the error, "TypeError: string indices must be integers, not str"
How would I use a string to call a previously defined dictionary that shares the same name?

You can use a variable via its name as string using exec:
dic1 = {'k': 'dic2'}
dic2 = {'key_1': 'value'}
exec('print ' + dic1['k'] + "['key_1']")

Short answer: I don't think you can.
However, if the dictionary explore_items uses the dicts in questions as its keys, this should work.
ETA to clarify:
explore_items = {{dict1}: a, {dict2}:b, {dict3}:c}
random_key= random.choice(explore_items.keys())