TypeError: 'dict_keys' object is not subscriptable (Python)

# Table of Contents

1. TypeError: 'dict_keys' object is not subscriptable
2. TypeError: 'generator' object is not subscriptable in Python
3. TypeError: 'map' object is not subscriptable in Python

# TypeError: 'dict_keys' object is not subscriptable (Python)

The Python "TypeError: 'dict_keys' object is not subscriptable" occurs when we try to access a dict_keys object at a specific index.

To solve the error, convert the dict_keys object to a list, before accessing an index, e.g. list(my_dict.keys())[0].

Here is an example of how the error occurs.

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my_dict = {'name': 'Bobby Hadz', 'age': 30}

keys = my_dict.keys()

print(type(keys))  # 👉️ <class 'dict_keys'>

# ⛔️ TypeError: 'dict_keys' object is not subscriptable
print(keys[0])

Notice that the dict.keys() method returns a dict_keys object, not a list.

# Convert the dict_keys object to a list

To solve the error, pass the dict_keys object to the list constructor to convert it to a list before accessing a list item at a specific index.

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my_dict = {'name': 'Bobby Hadz', 'age': 30}

# ✅ Convert to a list
keys = list(my_dict.keys())

print(keys[0])  # 👉️ "name"
print(keys[1])  # 👉️ "age"
print(keys[0:2])  # 👉️ ['name', 'age']

The dict.keys() method returns a new view of the dictionary's keys.

Once you convert the dict_keys object to a list, you can also use list slicing.

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my_dict = {'name': 'Bobby Hadz', 'age': 30, 'country': 'Belgium'}

keys = list(my_dict.keys())

print(keys[0:2]) # 👉️ ['name', 'age']
print(keys[1:3]) # 👉️ ['age', 'country']

The syntax for list slicing is a_list[start:stop:step].

The start index is inclusive and the stop index is exclusive (up to, but not including).

If the start index is omitted, it is considered to be 0, if the stop index is omitted, the slice goes to the end of the list.

Python indexes are zero-based, so the first item in a list has an index of 0, and the last item has an index of -1 or len(a_list) - 1.

# TypeError: 'dict_values' or 'dict_items' object is not subscriptable

The solution is the same if you get one of the following errors:

• TypeError: 'dict_values' object is not subscriptable
• TypeError: 'dict_items' object is not subscriptable

You have to convert the dict_values or dict_items object to a list before accessing it at an index.

Here is an example that does that for dict_values.

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my_dict = {'name': 'Bobby Hadz', 'age': 30}

# ✅ convert to list
values = list(my_dict.values())


print(values[0])  # 👉️ "Bobby Hadz"
print(values[1])  # 👉️ 30

print(values[0:2])  # 👉️ ['Bobby Hadz', 30]

And here is an example that does that for dict_items.

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my_dict = {'name': 'Bobby Hadz', 'age': 30}

# ✅ Convert to a list
items = list(my_dict.items())


print(items[0])  # 👉️ ('name', 'Bobby Hadz')
print(items[1])  # 👉️ ('age', 30)

print(items[0:2])  # 👉️ [('name', 'Bobby Hadz'), ('age', 30)]

# Iterating over a dictionary's keys

You can iterate over a dictionary's keys without having to convert the dict_keys object to a list.

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my_dict = {'name': 'Bobby Hadz', 'age': 30, 'country': 'Belgium'}

for key in my_dict.keys():
    # name
    # age
    # country
    print(key)

On each iteration, we get access to the current key and print the result.

If you need to access the value of the current iteration, use the dict.items() method instead.

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my_dict = {'name': 'Bobby Hadz', 'age': 30, 'country': 'Belgium'}

for key, value in my_dict.items():
    # name Bobby Hadz
    # age 30
    # country Belgium
    print(key, value)

# Handling out-of-range exceptions with a try/except

Note that if you try to access a list index that is out of bounds, you would get an error.

You can use a try/except statement if you need to handle that.

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my_dict = {'name': 'Bobby Hadz', 'age': 30}

keys = list(my_dict.keys())

try:
    print(keys[100])
except IndexError:
    print('index out of bounds')  # 👉️ this runs

The example catches the IndexError that is thrown if the index is out of bounds.

Note that an IndexError is not raised when you use list slicing, even if the specified indices do not exist.

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my_dict = {'name': 'Bobby Hadz', 'age': 30, 'country': 'Belgium'}

keys = list(my_dict.keys())

print(keys[100:200])  # 👉️ []
print(keys[1:100])  # 👉️ ['age', 'country']

The list constructor takes an iterable, such as a dict_keys object, and converts it to a list.

The list constructor takes an iterable that may be a sequence, a container that supports iteration or an iterator object.

You should only use square brackets to access subscriptable objects.

The subscriptable objects in Python are:

• list
• tuple
• dictionary
• string

All other objects have to be converted to a subscriptable object by using the list(), tuple(), dict() or str() classes to be able to use bracket notation.

Subscriptable objects implement the __getitem__ method whereas non-subscriptable objects do not.

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a_list = [2, 4, 6, 8]

# 👇️ <built-in method __getitem__ of list object at 0x7f71f3252640>
print(a_list.__getitem__)

# Table of Contents

1. TypeError: 'generator' object is not subscriptable in Python
2. TypeError: 'map' object is not subscriptable in Python

# TypeError: 'generator' object is not subscriptable in Python

The Python "TypeError: 'generator' object is not subscriptable" occurs when we try to access a generator object at a specific index.

To solve the error, pass the generator to the list constructor, e.g. list(gen)[0].

Here is an example of how the error occurs

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def g():
    yield 1

    yield 2

    yield 3


gen = g()

print(type(gen))

# ⛔️ TypeError: 'generator' object is not subscriptable
print(gen[0])

We used square brackets to try to access the element at index 0, but the generator object is not subscriptable.

We can get around this by converting the generator object to a list.

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def g():
    yield 1

    yield 2

    yield 3

# ✅ convert generator object to list
my_list = list(g())

print(my_list)  # 👉️ [1, 2, 3]

print(my_list[0])  # 👉️ 1
print(my_list[1])  # 👉️ 2

List objects are subscriptable, so we can access the element at a specific index after converting the generator object to a list.

You can iterate over a generator with a simple for loop.

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def g():
    yield 1

    yield 2

    yield 3


gen = g()

for i in gen:
    print(i)  # 👉️ 1, 2, 3

Alternatively, you can pass the generator to the next() function to retrieve the next item.

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def g():
    yield 1

    yield 2

    yield 3


gen = g()

print(next(gen))  # 👉️ 1
print(next(gen))  # 👉️ 2
print(next(gen))  # 👉️ 3

Note that if you try to access a list index that is out of bounds, you will get an error. You can use a try/except statement if you need to handle that.

Copied!
def g():
    yield 1

    yield 2

    yield 3


my_list = list(g())

try:
    print(my_list[100])
except IndexError:
    print('index out of bounds')  # 👉️ this runs

The example catches the IndexError that is thrown if the index is out of bounds.

The list constructor takes an iterable, such as a generator object, and converts it to a list.

The list constructor takes an iterable that may be a sequence, a container that supports iteration or an iterator object.

You should only use square brackets to access subscriptable objects.

The subscriptable objects in Python are:

• list
• tuple
• dictionary
• string

All other objects have to be converted to a subscriptable object by using the list(), tuple(), dict() or str() classes to be able to use bracket notation.

Subscriptable objects implement the __getitem__ method whereas non-subscriptable objects do not.

Copied!
a_list = ['bobby', 'hadz', 'com']

# 👇️ <built-in method __getitem__ of list object at 0x7f71f3252640>
print(a_list.__getitem__)

# TypeError: 'map' object is not subscriptable in Python

The Python "TypeError: 'map' object is not subscriptable" occurs when we try to access a map object at a specific index.

To solve the error, convert the map object to a list before accessing it at an index, e.g. new_list = list(map(int, a_list)).

Here is an example of how the error occurs.

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a_list = ['2', '4', '6', '8']


new_list = map(int, a_list)
print(new_list)  # 👉️ <map object at 0x7fde832679a0>

# ⛔️ TypeError: 'map' object is not subscriptable
print(new_list[0])

In Python 3, the map() function returns a map object, not a list.

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a_list = ['2', '4', '6', '8']

new_list = list(map(int, a_list))
print(new_list)  # 👉️ [2, 4, 6, 8]

print(new_list[0])  # 👉️ 2

The map() function takes a function and an iterable as arguments and calls the function with each item of the iterable.

The function returns a map object and map objects are not subscriptable (cannot be accessed at an index).

You can use square brackets if you need to access:

• a list at a specific index
• a tuple at a specific index
• a string at a specific index
• a specific key in a dictionary

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a_list = ['2', '4', '6', '8']

new_list = []

map_obj = map(int, a_list)

for item in map_obj:
    print(int(item))

    new_list.append(int(item))

print(new_list) # 👉️ [2, 4, 6, 8]

print(new_list[0])  # 👉️ 2

print(new_list[:2])  # 👉️ [2, 4]

Map objects are evaluated lazily, so we used a for loop to iterate over the object.

You can optionally append the result of calling a function with each item to a list.

A better approach than having to convert a map object to a list is to use a list comprehension.

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a_list = ['2', '4', '6', '8']

new_list = [int(item) for item in a_list]

print(new_list)  # 👉️ [2, 4, 6, 8]

We used a list comprehension to iterate over the original list.

On each iteration, we call the int() class with the current item and return the result.

The list comprehension returns a new list containing the results.

You can also use a list comprehension or the map function with user-defined functions.

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def do_math(a):
    return a + 100


a_list = [2, 4, 6, 8]

result = list(map(do_math, a_list))
print(result)  # 👉️ [102, 104, 106, 108]
print(result[0])  # 👉️ 102

result = [do_math(item) for item in a_list]
print(result)  # 👉️ [102, 104, 106, 108]
print(result[0])  # 👉️ 102

The error basically means that the object cannot be accessed using square brackets.

You should only use square brackets to access subscriptable objects.

The subscriptable objects in Python are:

• list
• tuple
• dictionary
• string

All other objects have to be converted to a subscriptable object by using the list(), tuple(), dict() or str() classes to be able to use bracket notation.

Subscriptable objects implement the __getitem__ method whereas non-subscriptable objects do not.

Copied!
a_list = [1, 2, 3]

# 👇️ <built-in method __getitem__ of list object at 0x7f71f3252640>
print(a_list.__getitem__)

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Count the number of Keys in a Dictionary in Python
• Check if a nested key exists in a Dictionary in Python
• Check if multiple Keys exist in a Dictionary in Python
• Assign a dictionary Key or Value to variable in Python