Menu
I am consuming several endpoints of an API that is very verbose in the data it returns. I would like to provide a subset of this data to another piece of code elsewhere.
Suppose I am given several dictionaries like this (which I plan to loop through and filter):
asset = {
'id': 1,
'name': 'MY-PC',
'owner': 'me',
'location': 'New York City',
'model': {
'id': 1,
'name': 'Surface',
'manufacturer': {
'id': 1,
'name': 'Microsoft'
}
}
}
I want to create a function that will take that dictionary in, along with a "mask" which will be used to create a new dictionary of only the allowed items. This might be an example mask (though, I can work with whatever format makes the resulting code the most concise):
mask = {
'id': True,
'name': True,
'model': {
'id': True,
'name': True,
'manufacturer': {
'name': True
}
}
}
The function should then return this:
mask = {
'id': 1,
'name': 'MY-PC',
'model': {
'id': 1,
'name': 'Surface',
'manufacturer': {
'name': 'Microsoft'
}
}
}
Is there something already built into Python 3 that would help aid in this? It looks like if I have to do this manually, it's going to get quite ugly quickly. I found itertools.compress, but that seems like it's for lists and won't handle the complexity of dictionaries.
885
Access Values using get() Another way to access value(s) in a nested dictionary ( employees ) is to use the dict. get() method. This method returns the value for a specified key. If the specified key does not exist, the get() method returns None (preventing a KeyError ).
Addition of elements to a nested Dictionary can be done in multiple ways. One way to add a dictionary in the Nested dictionary is to add values one be one, Nested_dict[dict][key] = 'value'. Another way is to add the whole dictionary in one go, Nested_dict[dict] = { 'key': 'value'}.
If you only need the dictionary values -0.3246 , -0.9185 , and -3985 use: your_dict. values() . If you want both keys and values use: your_dict. items() which returns a list of tuples [(key1, value1), (key2, value2), ...] .
To create a nested dictionary, simply pass dictionary key:value pair as keyword arguments to dict() Constructor. You can use dict() function along with the zip() function, to combine separate lists of keys and values obtained dynamically at runtime.
You can recursively build a new dict from the mask by selecting only values corresponding in the main dict:
def prune_dict(dct, mask):
result = {}
for k, v in mask.items():
if isinstance(v, dict):
value = prune_dict(dct[k], v)
if value: # check that dict is non-empty
result[k] = value
elif v:
result[k] = dct[k]
return result
print(prune_dict(asset, mask))
{'id': 1,
'model': {'id': 1, 'manufacturer': {'name': 'Microsoft'}, 'name': 'Surface'},
'name': 'MY-PC'}
This would be a good chance to use recursion, here is some sample code I haven't tested:
def copy(asset, result, mask):
for key_name, value in mask.items():
if value == True:
result[key_name] = asset[key_name]
else:
result[key_name] = x = {}
copy(asset[key_name], x, value)
y = {}
copy(asset, y, mask)
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
