1. You can update many keys on the same statement.
my_dict.update(other_dict)
In this case you don't have to know how many keys are in the other_dict. You'll just be sure that all of them will be updated on my_dict.
2. You can use any iterable of key/value pairs with dict.update
As per the documentation you can use another dictionary, kwargs, list of tuples, or even generators that yield tuples of len 2.
3. You can use the update method as an argument for functions that expect a function argument.
Example:
def update_value(key, value, update_function):
update_function([(key, value)])
update_value("k", 3, update_on_the_db) # suppose you have a update_on_the_db function
update_value("k", 3, my_dict.update) # this will update on the dict
Top answer 1 of 3
50
1. You can update many keys on the same statement.
my_dict.update(other_dict)
In this case you don't have to know how many keys are in the other_dict. You'll just be sure that all of them will be updated on my_dict.
2. You can use any iterable of key/value pairs with dict.update
As per the documentation you can use another dictionary, kwargs, list of tuples, or even generators that yield tuples of len 2.
3. You can use the update method as an argument for functions that expect a function argument.
Example:
def update_value(key, value, update_function):
update_function([(key, value)])
update_value("k", 3, update_on_the_db) # suppose you have a update_on_the_db function
update_value("k", 3, my_dict.update) # this will update on the dict
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22
d.update(n) is basically an efficient implementation of the loop
for key, value in n.items():
d[key] = value
But syntactically, it also lets you specify explicit key-value pairs without building a dict, either using keyword argumetns
d.update(a=1, b=2)
or an iterable of pairs:
d.update([('a', 1), ('b', 2)])
W3Schools
w3schools.com › python › ref_dictionary_update.asp
Python Dictionary update() Method
The specified items can be a dictionary, or an iterable object with key value pairs. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com · If you want to report an error, or if you want to make a suggestion, send us an e-mail: help@w3schools.com · HTML Tutorial CSS Tutorial JavaScript Tutorial How To Tutorial SQL Tutorial Python Tutorial W3.CSS Tutorial Bootstrap Tutorial PHP Tutorial Java Tutorial C++ Tutorial jQuery Tutorial
defaultdict vs update
d1 = {"a": 1, "b": 2} d2 = {"b": 3, "c": 4} d3 = defaultdict(d1) d1.update(d2) d3.update(d2) # now d1 == d2 == {"a": 1, "b": 3, "c": 4} # let's delete a key d1.pop("b") d1["b"] # > Exception, as no value for b is store d3.pop("b") d3["b"] # > 2 as the value is taken from the defaults So there actually is a difference if I understand the documentation right More on reddit.com
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January 22, 2019Looping through multiple nested dictionaries and updating a key:value pair if condition is met
Here you go. Also I think if you want to convert seconds to nanoseconds you should be multiplying by 1e9, not dividing, right? for key, value in data.items(): if isinstance(value, dict) and "totalTime" in value: data[key]["totalTime"] = data[key]["totalTime"] * 1e9 More on reddit.com
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September 15, 2019Videos
02:05
Python Dictionary Update() Method - YouTube
01:40
How to Update values in a Python Dictionary - YouTube
04:44
Updating and Adding Items in a Dictionary | Python Tutorial | Python ...
03:07
Python Dictionary - add and update items from a dictionary - YouTube
06:55
Python Basics: Updating Dictionaries Made Easy - YouTube
GeeksforGeeks
geeksforgeeks.org › python › python-dictionary-update-method
Python Dictionary update() method - GeeksforGeeks
2 weeks ago - Example 1: In this example, new key-value pairs are added to the dictionary. ... Explanation: update({'y': 20}) adds new key 'y'.
Spark By {Examples}
sparkbyexamples.com › home › python › python dictionary update() method
Python Dictionary update() Method -
May 31, 2024 - The update() method modifies the original dictionary in-place. It doesn’t return a new dictionary; instead, it updates the calling dictionary with the elements from the provided dictionary or iterable.
DataCamp
datacamp.com › tutorial › python-dictionary-append
Python Dictionary Append: How to Add Key-Value Pairs | DataCamp
August 6, 2024 - In this example, first_dictionary and second_dictionary are merged into a new dictionary merged_dictionary. The merge operator (|) combines the key-value pairs from both dictionaries, making it a quick and convenient method for merging dictionaries. For in-place updates, Python 3.9 also introduced the update |= operator.
How To Guides
hostingseekers.com › home › how to add and update dictionary in python?
How to Add and Update dictionary in Python?
February 27, 2025 - Ans. Use update() or the |= operator (Python 3.9+). ... Ans. Loop through the dictionary and modify values.
Career Karma
careerkarma.com › blog › python › python dictionary update
Python Dictionary Update: A Complete Guide | Career Karma
December 1, 2023 - This allows us to update new_stock to be equal to True in our book dictionary. Finally, we print out our revised dictionary using print(book). The Python dictionary update() method allows you to update the contents of a dictionary.
The Teclado Blog
blog.teclado.com › python-updating-dictionaries
Updating Python Dictionaries
October 26, 2022 - In this snippet post we look at the update method for dictionaries. We can use update to change several values at once or extend dictionaries with new keys.
Oreate AI
oreateai.com › blog › using-the-python-dictionary-update-method › 0c2a1bcf87689d70361351213c5e7967
Using the Python Dictionary Update Method - Oreate AI Blog
December 22, 2025 - Syntax of the update method The syntax for the update method is as follows: dict.update(dict2) Here, 'dict' is the dictionary to be updated and 'dict2' can be another dictionary or an iterable sequence of key-value pairs to add to 'dict'.
Replit
replit.com › home › discover › how to update a dictionary in python
How to update a dictionary in Python | Replit
3 weeks ago - After user_settings is updated with a new notification preference, the merge is run again. This creates a brand-new active_settings dictionary, showing how you can dynamically rebuild configurations to reflect changes. A defaultdict streamlines text analysis by letting you loop through words and increment their counts directly, as it automatically handles any word the first time it appears. from collections import defaultdict text = "Python is amazing Python is a great language to learn" words = text.lower().split() frequency = defaultdict(int) for word in words: frequency[word] += 1 print(dict(frequency))
Educative
educative.io › answers › how-to-update-and-remove-elements-from-a-python-dictionary
How to update and remove elements from a Python dictionary
The example below demonstrates both the addition and update operations on the existing dictionary object. my_dict = {'Name': 'Henry', 'Age': 16, 'Subject': 'English'} print("The student who left is", my_dict.get('Name')) ... The update method is an alternative method to modify the value of an existing item. sample_dict = {"java" : 1, "python" : 2, "nodejs" : 3}
Quora
quora.com › How-do-I-update-key-and-value-in-dictionary-in-python
How to update key and value in dictionary in python - Quora
Python (programming langu... ... You can update a dictionary by adding a new entry or a key-value pair, modifying an existing entry, or deleting an existing entry .
Plain English
python.plainenglish.io › updating-python-dictionaries-a-step-by-step-guide-ebfc01f19436
Updating Python Dictionaries: A Step-by-Step Guide | by Shantun Parmar | Python in Plain English
October 30, 2024 - update() Method: Our secret weapon for rebuilding dictionaries is update() method. It combines the original dictionary with another dictionary or like data structure as its argument.
AskPython
askpython.com › home › how to update a python dictionary?
How to Update a Python Dictionary? - AskPython
August 6, 2022 - The function does not return any values, rater it updates the same input dictionary with the newly associated values of the keys. ... dict = {"Python":100,"Java":150} up_dict = {"Python":500} print("Dictionary before updation:",dict) dict.update(up_dict) print("Dictionary after updation:",dict)
Top answer 1 of 8
53
Python has this feature built-in:
>>> d = {'b': 4}
>>> d.update({'a': 2})
>>> d
{'a': 2, 'b': 4}
Or given you're not allowed to use dict.update:
>>> d = dict(d.items() + {'a': 2}.items()) # doesn't work in python 3
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31
With python 3.9 you can use an |= update operator:
>>> d = {'b': 4}
>>> d |= {'a': 2}
>>> d
{'a': 2, 'b': 4}
Python Central
pythoncentral.io › python-dictionary-update-method-how-to-add-change-or-modify-values
Python Dictionary Update() Method: How To Add, Change, Or Modify Values | Python Central
January 30, 2024 - This article discusses how you can use the update() function to modify the keys of dictionaries.
Skytowner
skytowner.com › explore › python_dictionary_update_method
Python Dictionary | update method with Examples
Python's dict.update(~) method updates the dictionary with the elements from another iterable of key/value pairs.
Python Reference
python-reference.readthedocs.io › en › latest › docs › dict › update.html
update — Python Reference (The Right Way) 0.1 documentation
Required. Either another dictionary object or an iterable of key:value pairs (iterables of length two). If keyword arguments are specified, the dictionary is then updated with those key:value pairs.
Python Guides
pythonguides.com › python-dictionary-update
Python Dictionary Update
January 12, 2026 - Let’s dive into the different methods I use to keep my Python dictionaries up to date. The most common way I perform a dictionary update is by using the Python built-in method .update().
LeetCode
leetcode.com › problems › word-search
Word Search - LeetCode
Can you solve this real interview question? Word Search - Given an m x n grid of characters board and a string word, return true if word exists in the grid. The word can be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring.