Python dict object has no attribute append

AttributeError: ‘dict’ object has no attribute ‘append’

The python AttributeError: ‘dict’ object has no attribute ‘append’ error happens when the append() attribute is called in the dict object. The dict object does not support the attribute append(). The elements can be added by assignment operator in dict. If the append() function is called in the ‘dict’, the error AttributeError: ‘dict’ object has no attribute ‘append’ will be thrown.

The python AttributeError: ‘dict’ object has no attribute ‘append’ error occurs when you try to append a value in a dict object. The dict should be modified as list or the values should be added as key value in the dict object. Before calling the append method, the object type should be verified.

The python dict contains a key value pair element. You can store or retrieve values using the key. The value can be accessed as a python list. The dict does not support attributes such as the append (). The python dict object is used for values in the key value pair and the values can be accessed using the key.

Exception

The python AttributeError: ‘dict’ object has no attribute ‘append’ error will be seen as below the stack trace. The python interpreter can not append a value in dict. The error will be seen as follows.

Traceback (most recent call last): File "/Users/python/Desktop/test.py", line 2, in a.append(' World') AttributeError: 'dict' object has no attribute 'append' [Finished in 0.0s with exit code 1]

How to reproduce this error

The error AttributeError: ‘dict’ object has no attribute ‘append’ can be reproduced in a dict object. If you call the append() function in a dict object, an error will occur. Create a dict object and store it in a variable. call the append function with an argument. The dict object did not locate the append() function. Therefore, the error AttributeError: ‘dict’ object has no attribute ‘append’ will be thrown.

Program

a = <>; a.append(' World') print a

Output

Traceback (most recent call last): File "/Users/python/Desktop/test.py", line 2, in a.append(' World') AttributeError: 'dict' object has no attribute 'append' [Finished in 0.0s with exit code 1]

Root Cause

The python class is a collection of data and functionality. The object in python is an enclosed collection of data and functionality identified as a class variable. The attribute in python is the collection of class-related data and functionality. These attributes are available for all class objects. The Attribute error is thrown if the attribute append is not supported by dict object.

The attributes of a class object will be accessed using the dot operator. if a python variable uses dot operator, the variable must be assigned with an object and the attribute must be supported by the object class. If the variable is assigned with a python dict object and the attribute append is called, the attribute error AttributeError: ‘dict’ object has no attribute ‘append’ will be thrown.

Solution 1

If the python variable is assigned to the dict object instead of the python list, the error AttributeError: ‘dict’ object has no attribute ‘append’ would occur. The python variable should be assigned to the python list instead of the python dict object. The example below illustrates how to create a python list to use the append function.

Program

a = []; a.append(' World') print a

Output

Solution 2

If the python variable is assigned with a dict object and if you call the append function, the error AttributeError: ‘dict’ object has no attribute ‘append’ will occur. The python dict object should be assigned with a value using assignment operator as a key value pair. The example below illustrates how to assign a key value pair in a dict object.

Program

Output

Solution 3

If you want to use the append function in a dict object, the dict object should have a list as a key value. The key is added to the dict object with a value of the type list. The following example would demonstrate how to create a key with a value of the type list and how to use append function in a dict object.

Program

a = <>; a['key']= [] a['key'].append('val') print a

Output

Solution 4

The python variable should be checked for the required type or not before the append attribute is invoked. A list supports the append attribute. The python object must be verified as a list. If the python object is not a list, it should not be called the append attribute.

In the example below, the type of the python variable is verified as a list. If the variable type is list, the append attribute will be invoked. If the type of the python variable is not a list, the append function will not be invoked. the append code will be ignored for the execution. Hence, the error AttributeError: ‘dict’ object has no attribute ‘append’ will not occur.

Program

a = <>; if type(a) is list: a.append(' World') print a

Output

Solution 5

If the data type of the variable is unknown, the attribute will be invoked with try and except block. The try block will execute if the python variable contains list object. Otherwise, the except block will handle the error.

In the example below, the append() function is added with in the try block. if the python variable is assigned with a dict object, the error will be thrown. the error will be handled with except block. The except block code will be executed and printed the value in the console. If the python variable contains list, the append method will be executed and the except block will be ignored.

Program

a = <>; try : a.append(' World') except : print 'error'; print a

Output

error Hello [Finished in 0.0s]

Источник

How to Fix: Python AttributeError: ‘dict’ object has no attribute ‘append’

The Python AttributeError is a common one that can mean different things. In this tutorial, you’ll learn how to solve the Python AttributeError: ‘dict’ object has no attribute ‘append’ error. The solution to the error can be interpreted in different ways. This tutorial will guide you through various causes of the error as well as providing solutions to solving it.

By the end of this tutorial, you’ll have learned:

• What the Python AttributeError means and how to resolve it
• How to resolve the error by adding new items to Python dictionaries
• How to append to dictionary keys that are lists

What Does the Python AttributeError: ‘dict’ object has no attribute ‘append’ Mean?

The Python AttributeError: ‘dict’ object has no attribute ‘append’ error occurs when you try to use the .append() method to add items to a Python dictionary. What the error indicates is that Python dictionaries do not have a method called .append() .

Let’s see how we can raise the error:

# Raising a Python AttributeError values = values.append(3) # Raises: AttributeError: 'dict' object has no attribute 'append'

We can see that by applying the .append() to a Python dictionary, the error is raised.

We can verify that the method doesn’t exist by passing a dictionary into the dir() function:

# Checking Methods Available to Python Dictionaries values = print(dir(values)) # Returns: # ['__class__', '__class_getitem__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__ior__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__or__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__ror__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'items', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values']

By doing this, we can see all of the different attributes and methods that an object has available to it. This allows us to verify that the method doesn’t exist, meaning that the error is raised when we try to apply the method.

In the following three sections, you’ll learn how to resolve the error, depending on the situation you’re trying to use.

How to Resolve the AttributeError by Adding a New Item to a Python Dictionary

In order to add an item to a Python dictionary, you simply need to assign its key-value pair. This means that you do not need to use a method, such as append, in order to add new items to a dictionary. Say you have a dictionary and want to add the key-value pair of ‘age’:33 to it, you can simply directly assign this value.

Let’s see how you can do this using Python:

# Adding a New Key-Value Pair to a Dictionary values = values['c'] = 3 print(values) # Returns:

In doing this, we can see that we don’t actually need to use a method such as .append() to add a new item to a dictionary. Knowing this can prevent many different issues down the road for your code.

How to Resolve the AttributeError by Using a List

If you want to append an item to a Python object directly, you may want to consider switching the data type to a list. Lists are mutable and heterogeneous so you can add new items to them using the .append() method. This allows you to easily add a new item to the end of a list. Let’s see how we can define a new list and add new items to it:

# Adding New Items to a Python List values = [1, 2, 3] values.append(4) print(values) # Returns: [1, 2, 3, 4]

While this does change the problem statement of this tutorial, it’s a good thing to consider. When you’re simply wanting to add new items to a container, perhaps dictionaries aren’t the data type you were looking for.

How to Resolve the AttributeError by Appending to a List as a Dictionary Value

In some cases, you’ll want to append an item to a list that’s a value in a Python dictionary. For example, you may have a dictionary that looks like this: . In this case, it’s perfectly valid to want to append an item to the list that’s contained the in the dictionary.

In these cases, you can use the append method. However, instead of applying the method to the dictionary itself, you apply it to the key of a dictionary. Let’s see what this looks like:

# Appending to a List in a Dictionary values = values['ages'].append(64) print(values) # Returns: #

Let’s break down what we did in the code above:

1. We defined a dictionary that has a single key-value pair, where the value is a Python list
2. We then used the .append() method on the key of the dictionary
3. Finally, we printed our updated dictionary, which contained the appended value

Conclusion

In this tutorial, you learned how to resolve the Python AttributeError: ‘dict’ object has no attribute ‘append’ error. The error is raised when you attempt to apply the append method to a Python dictionary. Because Python dictionaries don’t have an append method, you need to use alternative methods to add new items to a dictionary. You first learned how to resolve the error by assigning a new key-value pair directly to the dictionary. Then, you learned how to resolve the error by using a list instead of a dictionary. Finally, you learned how to use the append method to add a new item to a list that’s a dictionary’s value.

Additional Resources

To learn more about related topics, check out the tutorials below:

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