Object of type int has no len python ошибка

In python, the error “TypeError: object of type ‘int’ has no len()” occurs when the length function is invoked on objects that does not support the length function. The length function is supported by iterable objects such as list, tuple, dictionary and string.

The length function is used to find the length of the string or the number of objects in a structured objects such as list, tuple and dictionary. The length function does not supported by the data types such as int, float, long, boolean, complex data types. If the length function is invoked on unsupported objects, the python interpreter will cause the error.

The purpose of the len() function is to determine the length of the list, tuple, dictation, or string. In this article, we can see what this error is, how this error can be resolved. The error would be thrown as like below.

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 2, in <module>
    print (len(s))
TypeError: object of type 'int' has no len()
[Finished in 0.2s with exit code 1]

Different Variation of the error

In different contexts the “TypeError: object of type ‘int’ has no len()” error is thrown in various forms in python. The numerous variations of TypeError are shown below.

TypeError: object of type 'NoneType' has no len()
TypeError: object of type 'int' has no len()
TypeError: object of type 'float' has no len()
TypeError: object of type 'long' has no len()
TypeError: object of type 'bool' has no len()
TypeError: object of type 'complex' has no len()
TypeError: object of type 'type' has no len()
TypeError: object of type 'builtin_function_or_method' has no len()

Root Cause

The root cause of this error is that the len() function is invoked on objects that are not supported to calculate the length. Iterable objects such as list, tuple, dictionary, and strings are supported to find the length of the elements in it.

The len() function does not make sense for types such as integer, float, boolean, long, complex. The Python interpreter will throw this error when the len() function is invoked on this.

How to reproduce this error

If the len() function is invoked for the unsupported objects such as int, float, boolean, long etc, this error will be thrown. calling the len() function for the unsupported objects to reproduce this error “TypeError: object of type ‘int’ has no len()” in python.

s=5
print (len(s))

Output

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 2, in <module>
    print (len(s))
TypeError: object of type 'int' has no len()
[Finished in 0.2s with exit code 1]

Solution 1

The len() function should only be used for iterable objects such as list, tuple, dictionary and string. Make sure you return any of the objects. Changing the primary data types to the iterable objects will resolve this error “TypeError: object of type ‘int’ has no len()” in python.

s = [5,4]
print (len(s))

Output

2

Solution 2

The len() function must be called before checking the object type. If the object is an iterable object, such as a list, tuple, dictionary, or string, the len() function will be called. Otherwise the error message “TypeError: object of type ‘int’ has no len()” will be shown to the user that the length of the object can not be found.

s=[2]
print type(s)
if type(s) in (list,tuple,dict, str): 
	print (len(s))
else:
	print "not a list"

Output

1

Solution 3

The length can not be determined if the argument for the len() function is None. The value of the argument must be checked for non-None before calling the len() function. The error message “TypeError: object of type ‘NoneType’ has no len()” will be shown as in the example below.

s=None
print (len(s))

Output

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 2, in <module>
    print (len(s))
TypeError: object of type 'NoneType' has no len()
[Finished in 0.1s with exit code 1]

Solution

s=None
print type(s)
if s is None : 
	print "a None value"
else:
	print (len(s))

Output

a None value

Solution 4

The length can not be determined if the argument for the len() function is a python type. The value of the argument must be checked for type before calling the len() function or default value is set. The error message “TypeError: object of type ‘type’ has no len()” will be shown as in the example below.

s=list
print len(s)

Output

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 2, in <module>
    print len(s)
TypeError: object of type 'type' has no len()
[Finished in 0.0s with exit code 1]

Solution

s=list()
print len(s)

Output

0

Solution 5

The length can not be determined if the argument for the len() function is a python build in function. The value of the argument must be checked before calling the len() function. The error message will be shown as in the example below.

s=len
print len(s)

Output

Traceback (most recent call last):
  File "/Users/python/Desktop/test.py", line 2, in <module>
    print len(s)
TypeError: object of type 'builtin_function_or_method' has no len()
[Finished in 0.1s with exit code 1]

Solution

s=(2,3)
print len(s)

Output

2

In this article, we will learn about the TypeError: object of type ‘int’ has no len.

What is TypeError: object of type ‘int’ has no len?

This error is generated when we try to calculate the length of an integer value. But integer don’t have any length. Thus the error is raised.

Let us understand it more with the help of an example.

Example

# Importing random module
import random 

# Using randit function of random module
var = random.randint(0, 20)

# Printing Random value
print("Random value: ",var)

# Printing length of variable
print("Length of variable: ",len(var))

Output

Random value:  18
  File "len.py", line 12, in <module>
    print("Length of variable: ",len(var))
TypeError: object of type 'int' has no len()

Explanation

In the above example, we imported the random module of python. There are various function available in random module of python. In this particular code, we used the randint() function. This function returns any random integer within the specified parameter value.

After generating the random integer we stored it in the variable ‘var’. And printed it in the next line. There’s no error encountered until now. But when we try to try to calculate the length of the variable ‘var’ in line-12 of the code. An error is encountered. This TypeError is raised because we were trying to calculate the length of an integer. And we know integers don’t have any length.

Solution

# Importing random module
import random 

# Using randit(start,end) function of random module
var = random.randint(0, 20)

# Printing Random value
print("Random value: ",var)

# Printing length of variable
print("Length of variable: ",len(str(var))) 

Output

Random value:  2
Length of variable:  1

Explanation

As discussed earlier we can not calculate the length of an integer. But we can calculate the length of the string. So what we can do is, change the integer value to the string. And then calculate the length of that string.

Here we used a built-in function str() to change ‘var’ to string.

Conclusion

This TypeError is raised when we try to calculate the length of an integer using len(). To work around this error we can convert the integer value to string. And then calculate the length of the string.

I have seen this data type error come up numerous times while working on my data analytics projects, and recently decided to investigate further. On initial inspection, it can seem a bit of a funny one, but in actual fact, it is quite straight forward.

Lets break it down and see what is going on

So in the below code, there are a number of things:

On line 1 we have a variable that is an integer. If we think about this logically, something that is a single numeric number cannot have a length.

An integer by design is purely to count up a number of apples or no of people, it cannot be viewed as having a length as it is descriptive of the number of occurrences of an object.

data = 100
print(type(data))
print(len(data))

Output Error:
<class 'int'>
Traceback (most recent call last):
  File "object of type int.py", line 3, in <module>
    print(len(data))
TypeError: object of type 'int' has no len()

So for it to in anyway allow a length to be calculated, the object needs to be one of the following data types:

• List
• String
• Tuple
• Dictionary

Opposite to an integer, these are datatypes that have values that would be more appropriate to having values that a length can be calculated on.

data = "100"
print(type(data))
print("Length of string is: ", len(data))

data = [100,200,300]
print(type(data))
print("Length of list is: ", len(data))

data = (100,200,300)
print(type(data))
print("Length of tuple is: ", len(data))

data = {"Age": 1, "Name": 2}
print(type(data))
print("Length of dictionary is: ", len(data))

And the output is:
<class 'str'>
Length of string is:  3
<class 'list'>
Length of list is:  3
<class 'tuple'>
Length of tuple is:  3
<class 'dict'>
Length of dictionary is:  2

In summary, to understand this error and fix it:

An integer describes the number of things that exist for an object, they are actually not the actual object in existence.

Anything that can have a length method applied to it actually exists and can be counted. In the above four examples, they are actually values that you could describe as existing as you can count each one of them.

The explanation here hopefully clears up the matter, if you have any questions leave a comment and I will answer for you!

Only iterable objects such as strings and lists have a length. If you try to calculate the length of a number, you’ll encounter the “TypeError: object of type ‘int’ has no len()” error.

In this guide, we discuss what this error means and why it is raised. We’ll explore an example of a code snippet with this error so we can walk through how to fix the issue.

TypeError: object of type ‘int’ has no len()

The len() method returns the length of an object. Consider the following program:

browsers = ["Microsoft Edge", "Mozilla Firefox", "Google Chrome")
print(len(browsers))

Our program returns “3”. This is the length of our Python list. The length of the “browsers” object can be calculated because it contains multiple values.

Strings, tuples, and lists all work with the len() method because they are sequences of values. Integer values do not have a length because they only represent one value. Integers store a number which does not have a “length” like any other iterable object.

An Example Scenario

We’re going to write a program that calculates how many customers at an electronics store are part of a loyalty club program. We’ll start with a list of dictionaries which each store information about our customers:

customers = [
	  { "name": "Lesley Jones", "loyalty": True },
	  { "name": "Benjamin Logan", "loyalty": True },
	  { "name": "Hannah Mason", "loyalty": False }
]

Our customers list contains three dictionaries. Next, use a for loop to calculate how many customers are loyalty club members:

number_of_loyalty = 0

for c in customers:
	     if c["loyalty"] == True:
		          number_of_loyalty += 1

We have defined a variable called “number_of_loyalty”. We use this to keep track of how many customers are in the loyalty club.

We calculate whether a customer is a loyalty club member by evaluating whether the value of “loyalty” in each dictionary is equal to True.

Next, print a message to the console that tells us how many customers are loyalty members:

print("Out of the {} customers at the store, {} of them are loyalty club members.".format(len(customers), len(number_of_loyalty)))

The .format() statement lets us add values into our string at specific positions. In this case, we are adding in two values to our string: the number of customers evaluated, and how many customers are in the loyalty club.

Let’s run our code to see if it works:

Traceback (most recent call last):
 File "main.py", line 13, in <module>
	    print("Out of the {} customers at the store, {} of them are loyalty club members.".format(len(customers), len(number_of_loyalty)))
TypeError: object of type 'int' has no len()

Our code stops working on line 13. This is the last line of our program.

The Solution

The error message tells us we have tried to use a method on an object that does not support that method. We’ve tried to calculate the length of an integer value.

In our print statement, we ask our program to evaluate the length of the “number_of_loyalty” value:

This is unnecessary because “number_of_loyalty” itself tracks how many loyalty club members there are. To fix this error, we can remove the len() from around the “number_of_loyalty” value so we can see the integer value it stores:

print("Out of the {} customers at the store, {} of them are loyalty club members.".format(len(customers), number_of_loyalty))

Let’s run our revised program:

Out of the 3 customers at the store, 2 of them are loyalty club members.

Our program calculates that two out of the three customers at the store are loyalty club members. This was the output we expected. If we look at our initial list, we can see that both “Lesley Jones” and “Benjamin Logan” are loyalty card members.

Conclusion

The “TypeError: object of type ‘int’ has no len()” error is raised when you try to find the length of an integer value. To fix this issue, remove the len() method from around any integer value in your program.

Now you have the knowledge you need to fix this common Python error like a pro!

Watch Now This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: Python’s len() Function

In many situations, you’ll need to find the number of items stored in a data structure. Python’s built-in function len() is the tool that will help you with this task.

There are some cases in which the use of len() is straightforward. However, there are other times when you’ll need to understand how this function works in more detail and how to apply it to different data types.

In this tutorial, you’ll learn how to:

• Find the length of built-in data types using len()
• Use len() with third-party data types
• Provide support for len() with user-defined classes

By the end of this article, you’ll know when to use the len() Python function and how to use it effectively. You’ll know which built-in data types are valid arguments for len() and which ones you can’t use. You’ll also understand how to use len() with third-party types, such as ndarray in NumPy and DataFrame in pandas, and with your own classes.

>>> help(len)
Help on built-in function len in module builtins:
len(obj, /)
    Return the number of items in a container.

>>> greeting = "Good Day!"
>>> len(greeting)
9

>>> office_days = ["Tuesday", "Thursday", "Friday"]
>>> len(office_days)
3

>>> london_coordinates = (51.50722, -0.1275)
>>> len(london_coordinates)
2

>>> len("")
0
>>> len([])
0
>>> len(())
0

>>> len(range(1, 20, 2))
10

>>> import random

>>> numbers = [random.randint(1, 20) for _ in range(20)]

>>> numbers
[3, 8, 19, 1, 17, 14, 6, 19, 14, 7, 6, 1, 17, 10, 8, 14, 17, 10, 2, 5]

>>> unique_numbers = set(numbers)
{1, 2, 3, 5, 6, 7, 8, 10, 14, 17, 19}

>>> len(unique_numbers)
11

>>> len({"James": 10, "Mary": 12, "Robert": 11})
3

>>> len({})
0

>>> len(5)
Traceback (most recent call last):
    ...
TypeError: object of type 'int' has no len()

>>> len(5.5)
Traceback (most recent call last):
     ...
TypeError: object of type 'float' has no len()

>>> len(True)
Traceback (most recent call last):
     ...
TypeError: object of type 'bool' has no len()

>>> len(5 + 2j)
Traceback (most recent call last):
     ...
TypeError: object of type 'complex' has no len()

>>> import random

>>> numbers = [random.randint(1, 20) for _ in range(20)]
>>> len(numbers)
20

>>> numbers_iterator = iter(numbers)
>>> len(numbers_iterator)
Traceback (most recent call last):
     ...
TypeError: object of type 'list_iterator' has no len()

>>> numbers_generator = (random.randint(1, 20) for _ in range(20))
>>> len(numbers_generator)
Traceback (most recent call last):
     ...
TypeError: object of type 'generator' has no len()

# username.py

username = input("Choose a username: [4-10 characters] ")

if 4 <= len(username) <= 10:
    print(f"Thank you. The username {username} is valid")
else:
    print("The username must be between 4 and 10 characters long")

$ python username.py
Choose a username: [4-10 characters] stephen_g
Thank you. The username stephen_g is valid

$ python username.py
Choose a username: [4-10 characters] sg
The username must be between 4 and 10 characters long

# username.py

usernames = []

print("Enter three options for your username")

while len(usernames) < 3:
    username = input("Choose a username: [4-10 characters] ")
    if 4 <= len(username) <= 10:
        print(f"Thank you. The username {username} is valid")
        usernames.append(username)
    else:
        print("The username must be between 4 and 10 characters long")

print(usernames)

>>> colors = ["red", "green", "blue", "yellow", "pink"]

>>> while len(colors) > 0:
...     print(f"The next color is {colors.pop(0)}")
...
The next color is red
The next color is green
The next color is blue
The next color is yellow
The next color is pink

>>> colors = ["red", "green", "blue", "yellow", "pink"]

>>> while colors:
...    print(f"The next color is {colors.pop(0)}")
...
The next color is red
The next color is green
The next color is blue
The next color is yellow
The next color is pink

>>> import random

>>> numbers = []
>>> while sum(numbers) <= 21:
...    numbers.append(random.randint(1, 10))

>>> numbers
[3, 10, 4, 7]

>>> numbers[len(numbers) - 1]
7

>>> numbers[-1]  # A more Pythonic way to retrieve the last item
7

>>> numbers.pop(len(numbers) - 1)  # You can use numbers.pop(-1)
7

>>> numbers
[3, 10, 4]

>>> import random

>>> numbers = [random.randint(1, 10) for _ in range(10)]
>>> numbers
[9, 1, 1, 2, 8, 10, 8, 6, 8, 5]

>>> first_half = numbers[: len(numbers) // 2]
>>> second_half = numbers[len(numbers) // 2 :]

>>> first_half
[9, 1, 1, 2, 8]
>>> second_half
[10, 8, 6, 8, 5]

$ python -m pip install numpy

>>> import numpy as np

>>> numbers = np.array([4, 7, 9, 23, 10, 6])
>>> type(numbers)
<class 'numpy.ndarray'>

>>> len(numbers)
6

>>> import numpy as np

>>> numbers = [
    [11, 1, 10, 10, 15],
    [14, 9, 16, 4, 4],
]

>>> numbers_array = np.array(numbers)
>>> numbers_array
array([[11,  1, 10, 10, 15],
       [14,  9, 16,  4,  4]])

>>> len(numbers_array)
2

>>> numbers_array.shape
(2, 5)

>>> len(numbers_array.shape)
2

>>> numbers_array.ndim
2

>>> import numpy as np

>>> array_3d = np.random.randint(1, 20, [2, 3, 4])
>>> array_3d
array([[[14,  9, 15, 14],
        [17, 11, 10,  5],
        [18,  1,  3, 12]],
       [[ 1,  5,  6, 10],
        [ 6,  3,  1, 12],
        [ 1,  4,  4, 17]]])

>>> array_3d.shape
(2, 3, 4)

>>> len(array_3d)
2

$ python -m pip install pandas

>>> import pandas as pd

>>> marks = {
    "Robert": [60, 75, 90],
    "Mary": [78, 55, 87],
    "Kate": [47, 96, 85],
    "John": [68, 88, 69],
}

>>> marks_df = pd.DataFrame(marks, index=["Physics", "Math", "English"])

>>> marks_df
         Robert  Mary  Kate  John
Physics      60    78    47    68
Math         75    55    96    88
English      90    87    85    69

>>> len(marks_df)
3

>>> marks_df.shape
(3, 4)

class DataFrame(NDFrame, OpsMixin):
    # ...
    def __len__(self) -> int:
        """
        Returns length of info axis, but here we use the index.
        """
        return len(self.index)

# ystring.py

class YString(str):
    def __init__(self, text):
        super().__init__()

    def __str__(self):
        """Display string as lowercase except for Ys that are uppercase"""
        return self.lower().replace("y", "Y")

    def __len__(self):
        """Returns the number of Ys in the string"""
        return self.lower().count("y")

>>> from ystring import YString

>>> message = YString("Real Python? Yes! Start reading today to learn Python")

>>> print(message)
real pYthon? Yes! start reading todaY to learn pYthon

>>> len(message)  # Returns number of Ys in message
4

>>> from ystring import YString

>>> first_test = "tomorrow"
>>> second_test = "today"

>>> bool(first_test)
True

>>> bool(YString(first_test))
False

>>> bool(second_test)
True

>>> bool(YString(second_test))
True

Watch Now This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: Python’s len() Function