Python dictionary replace values
PythonPython 3.xDictionaryPython Problem Overview
I have a dictionary with 20 000 plus entries with at the moment simply the unique word and the number of times the word was used in the source text (Dante's Divine Comedy in Italian).
I would like to work through all entries replacing the value with an actual definition as I find them. Is there a simple way to iterate through the keywords that have as a value a number in order to replace (as I research the meaning)?
The dictionary starts:
{'corse': 378, 'cielo,': 209, 'mute;': 16, 'torre,': 11, 'corsa': 53, 'assessin': 21, 'corso': 417, 'Tolomea': 21} # etc.
Sort of an application that will suggest a keyword to research and define.
Python Solutions
Solution 1 - Python
via dict.update() function
In case you need a declarative solution, you can use dict.update()
to change values in a dict.
Either like this:
my_dict.update({'key1': 'value1', 'key2': 'value2'})
or like this:
my_dict.update(key1='value1', key2='value2')
via dictionary unpacking
Since Python 3.5 you can also use dictionary unpacking for this:
my_dict = { **my_dict, 'key1': 'value1', 'key2': 'value2'}
Note: This creates a new dictionary.
via merge operator or update operator
Since Python 3.9 you can also use the merge operator on dictionaries:
my_dict = my_dict | {'key1': 'value1', 'key2': 'value2'}
Note: This creates a new dictionary.
Or you can use the update operator:
my_dict |= {'key1': 'value1', 'key2': 'value2'}
Solution 2 - Python
You cannot select on specific values (or types of values). You'd either make a reverse index (map numbers back to (lists of) keys) or you have to loop through all values every time.
If you are processing numbers in arbitrary order anyway, you may as well loop through all items:
for key, value in inputdict.items():
# do something with value
inputdict[key] = newvalue
otherwise I'd go with the reverse index:
from collections import defaultdict
reverse = defaultdict(list)
for key, value in inputdict.items():
reverse[value].append(key)
Now you can look up keys by value:
for key in reverse[value]:
inputdict[key] = newvalue
Solution 3 - Python
If you iterate over a dictionary you get the keys, so assuming your dictionary is in a variable called data
and you have some function find_definition()
which gets the definition, you can do something like the following:
for word in data:
data[word] = find_definition(word)
Solution 4 - Python
I think this may help you solve your issue.
Imagine you have a dictionary like this:
dic0 = {0:"CL1", 1:"CL2", 2:"CL3"}
And you want to change values by this one:
dic0to1 = {"CL1":"Unknown1", "CL2":"Unknown2", "CL3":"Unknown3"}
You can use code bellow to change values of dic0
properly respected to dic0to1
without worrying yourself about indexes in dictionary:
for x, y in dic0.items():
dic0[x] = dic0to1[y]
Now you have:
>>> dic0
{0: 'Unknown1', 1: 'Unknown2', 2: 'Unknown3'}
Solution 5 - Python
data = {key1: value1, key2: value2, key3: value3}
for key in data:
if key == key1:
data[key1] = change
print(data)
this will replace key1: value1 to key1: change