Python Dictionary

Filter a dictionary in Python using dictionary comprehension

How can we filter a dictionary on some conditions by not using the for and if statements? There are too many situations we should filter an iter...

Convert a dictionary to a json string in Python

You can convert a dictionary to a JSON string by `json.dumps()` in `json` module. python import json s = {'a': 1, 'b': 2} j = json.dump...

Python dictionary items() - Get key-value pairs of a dictionary

The `items()` returns pairs of a dictionary, each of which is a tuple of a key and value. python d = {'CA': 'California', 'NV': 'Nevada', '...

Python dictionary clear() - Remove all the elements from the dictionary

The `clear()` removes all the elements from a [dictionary](/python-dictionary). python d = {'CA': 'California', 'NV': 'Nevada', 'TX': 'Texa...

Python dictionary comprehension

You can create a dctionary from a list by so-called dictionary comprehension. python a = [2, 5, 8] d = {n: n + 1 for n in a} print(d) ...

Python dictionary

A Python dictionary is a set of pairs. python d = {'book': 97, 'pen': 145, 'note': 314} As a real dictionary consists of words and me...

Merge Python dictionaries - The difference of double asterisks operation and update method

The unpacking technique (from Python 3.5) enables you to merge some dictionaries. python a = {'apple': 3, 'lemon': 2} b = {'apple': 15, 'p...

Python dictionary copy (shallow copy and deep copy) - Difference of b=a.copy() and b=a

Python dictionary has `copy()` method that returns the same dictionary. python a = {'book': 97, 'pen': 145, } b = a.copy() print(b) ...

Python dictionary setdefault - Difference of get and setdefault

Python dictionary `setdefault()`, which is similar to [get()](/python-dictionary-get), returns the value of a given key. python d = { ...

Python dictionary get() - How to get the (default) value by a given key

The Python dictionary method `get()` returns the value of a given key. python d = { 'book': 28, 'pen': 145, } a = d.get('book...

Python dictionary values() - How to get values of a dictionary

The `values()` returns values of a [dictionary](/python-dictionary-basic) as a dict_values object. python d = {'book': 24, 'pen': '5'} v...

Python dictionary keys() - How to get all keys from a dictionary

The Python dictionary has `keys()` method that returns all keys of it as a dict_keys object. python d = {'book': 24, 'pen': '5'} keys = ...

Python dictionary and for loop: How to iterate the key and value of a dictionary in Python

You can iterate dictionary keys by using the for-in statement. python d = {'book': 24, 'pen': '5'} for k in d: print(k) # book ...

Sort a Python dictionary

A Python dictionary is a kind of set and doesn't essentially have an order. But it can be regarded as a list of tuples, and in fact, the `sorted...

Delete (Remove) an item from a dictionary in Python - How to use pop, del, clear

To delete an item from a dictionary, you can use `pop()`, `del()`, `clear()` methods. ## pop() python d = {'A': 2, 'B': 5, 'C': 13} p...

Python dictionary update() - Update the dictionary with the other dictionary or the key-value pairs

The `update()` updates a dictionary with the other dictionary. python d = {'x': 1, 'y': 2} d2 = {'m': 4, 'n': 5} d.update(d2) print(...

Python dictionary length - How to count all the elements in a dictionary

The `len()` returns the number of items in a Python dictionary. python a = {'CA': 'California', 'NV': 'Nevada', 'TX': 'Texas'} b = {'book'...

How to check if a key or value exists in a Python dictionary

A Python dictionary is a set of pairs like that. python d = {'book': 5, 'pen': 9} It means there are 5 books and 9 pens. In this case...