Python | Get dictionary keys as a list

Given a dictionary, write a Python program to get the dictionary keys as a list. 

Examples:

Input  : {1:'a', 2:'b', 3:'c'}
Output : [1, 2, 3]

Input  : {'A' : 'ant', 'B' : 'ball'}
Output : ['A', 'B']

Method 1: Get dictionary keys as a list using dict.keys()

The dict.keys() method in Python Dictionary, returns a view object that displays a list of all the keys in the dictionary in order of insertion.

Python3

# Driver program
dict = {1: 'Geeks', 2: 'for', 3: 'geeks'}
print(dict.keys())

Output:

dict_keys([1, 2, 3])

Method 2: Get dictionary keys as a list using dict.keys()

Python list() function takes any iterable as a parameter and returns a list. In Python iterable is the object you can iterate over.

Python3

mydict = {1: 'Geeks', 2: 'for', 3: 'geeks'}
keysList = list(mydict.keys())
print(keysList)

Output:

[1, 2, 3]

Method 3: Get dictionary keys as a list using For Loop and append method

In this method, we will iterate over each key using the dict.keys() function and append them to a new list named as a list.

Python3

# Python program to get
# dictionary keys as list

def getList(dict):
    list = []
    for key in dict.keys():
        list.append(key)

    return list

# Driver program
dict = {1:'Geeks', 2:'for', 3:'geeks'}
print(getList(dict))

Output:

[1, 2, 3]

Method 4:  Dictionary Keys to List using List Comprehension

Here, we will try to shorten our code using list comprehension in Python.

Python3

dict = {1: 'Geeks', 2: 'for', 3: 'geeks'}
keysList = [key for key in dict]
print(keysList)

Output:

[1, 2, 3]

Method 5: Dictionary Keys to List using Unpacking with *

Unpacking with * works with any object that is iterable and, since dictionaries return their keys when iterated through, you can easily create a list by using it within a list literal. 

Python3

def getList(dict):

    return [*dict]

# Driver program
dict = {'a': 'Geeks', 'b': 'For', 'c': 'geeks'}
print(getList(dict))

Output:

['a', 'b', 'c']

Method 6: Dictionary Keys to List using itemgetter

The itemgetter from the operator module returns a callable object that fetches an item from its operand using the operand’s __getitem__() method. This method is then mapped to dict.items() and then typecasted to list. 

Python3

from operator import itemgetter


def getList(dict):

    return list(map(itemgetter(0), dict.items()))

# Driver program
dict = {'a': 'Geeks', 'b': 'For', 'c': 'geeks'}
print(getList(dict))

Output:

['a', 'b', 'c']