def func(dct):
dct.clear()
dct.update({
'a': 5
}) You can mutate a dictionary within a method, because it is passed by reference, but in your case you're simply creating a new dictionary altogether. Since your variable dict is within a method, it doesn't share the same scope as the outer contents, and so refers to a new variable. If you want to overwrite it altogether, consider: def func(dct):
return {
'a': 5
}
dct = func(dct)
Suggestion : 2
Program to replace dictionary value for the given keys in another dictionary,Python program to convert key-value list to flat dictionary – Dictionary Flattening, Here, we are going to learn how to replace dictionary value for the given keys in another dictionary in Python? Submitted by Shivang Yadav, on March 25, 2021 ,We have two dictionaries, one with values and another consisting of the key-value pairs. We need to print the dictionary after replacing values for keys present in replace dictionary.
Example:
Dictionary: ['scala': 8, 'Javascript': 7, 'Python': 1, 'C++': 5, 'Java': 3] ReplaceDictionary: ['Javascript': 2, 'C++': 9] UpdatedDictionary: ['scala': 8, 'Javascript': 2, 'Python': 1, 'C++': 9, 'Java': 3]
Program to replace dictionary value for the given keys in another dictionary
# Python program to replace dictionary value # for the given keys in another dictionary # Initialising dictionary myDict = { 'Scala': 2, 'Javascript': 1, 'Python': 8, 'C++': 1, 'Java': 4 } updateDict = { "Scala": 10, "Python": 17 } print("Dictionary = ", end = " ") print(myDict) # Updating dictionary using update values for sub in myDict: if sub in updateDict: myDict[sub] = updateDict[sub] # Printing the dictionary print("Updated dictionary = ", end = " ") print(myDict)
Output:
Dictionary = { 'C++': 1, 'Javascript': 1, 'Python': 8, 'Scala': 2, 'Java': 4 } Updated dictionary = { 'C++': 1, 'Javascript': 1, 'Python': 17, 'Scala': 10, 'Java': 4 }
Suggestion : 3
The update() method updates the dictionary with the elements from another dictionary object or from an iterable of key/value pairs.,update() method updates the dictionary with elements from a dictionary object or an iterable object of key/value pairs.,The update() method takes either a dictionary or an iterable object of key/value pairs (generally tuples).,Note: The update() method adds element(s) to the dictionary if the key is not in the dictionary. If the key is in the dictionary, it updates the key with the new value.
Example
marks = { 'Physics': 67, 'Maths': 87 } internal_marks = { 'Practical': 48 } marks.update(internal_marks) print(marks) # Output: { 'Physics': 67, 'Maths': 87, 'Practical': 48 }
Example
marks = { 'Physics': 67, 'Maths': 87 } internal_marks = { 'Practical': 48 } marks.update(internal_marks) print(marks) # Output: { 'Physics': 67, 'Maths': 87, 'Practical': 48 }
The syntax of update() is:
Example 1: Working of update()
d = { 1: "one", 2: "three" } d1 = { 2: "two" } # updates the value of key 2 d.update(d1) print(d) d1 = { 3: "three" } # adds element with key 3 d.update(d1) print(d)
Suggestion : 4
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)?,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).,If you are processing numbers in arbitrary order anyway, you may as well loop through all items:,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.
The dictionary starts:
{ 'corse': 378, 'cielo,': 209, 'mute;': 16, 'torre,': 11, 'corsa': 53, 'assessin': 21, 'corso': 417, 'Tolomea': 21 } # etc.
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