Pickle EOFError: Ran out of input in Python [Solved]

# Pickle EOFError: Ran out of input in Python [Solved]

The Python "Pickle EOFError: Ran out of input" occurs when the file you are trying to open and load is empty.

To solve the error, check if the size of the file is greater than 0 bytes or handle the EOFError exception.

Here is an example of how the error occurs.

main.py

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import pickle

with open('employees.txt', 'rb') as my_file:
    unpickler = pickle.Unpickler(my_file)
    employee_data = unpickler.load()
    print(employee_data)

eoferror ran out of input in python with pickle

The code sample assumes that you have an employees.txt file that is empty.

One way to solve the error is to check if the file's size is greater than 0 bytes before using pickle.

main.py

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import os
import pickle

file_path = 'employees.txt'

if os.path.getsize(file_path) > 0:
    with open(file_path, 'rb') as my_file:
        unpickler = pickle.Unpickler(my_file)
        employee_data = unpickler.load()
        print(employee_data)
else:
    print('The file is empty')

check if file is empty before using pickle

The os.path.getsize() method takes a file path as a parameter and returns the size of the file in bytes.

The if statement checks that the file has a size of greater than 0 bytes (is not empty).

The file in the example is empty, so the else block runs.

Here is a more complete example that writes to a file and then reads from it using pickle.

main.py

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import os
import pickle

file_path = 'employees.txt'

employees = {
    'name': ['Alice', 'Bobby Hadz', 'Carl'],
    'age': [29, 30, 31]
}

with open(file_path, 'wb') as employees_file:
    pickle.dump(employees, employees_file)

if os.path.getsize(file_path) > 0:
    with open(file_path, 'rb') as my_file:
        unpickler = pickle.Unpickler(my_file)
        employee_data = unpickler.load()
        print(employee_data)
else:
    print('The file is empty.')

write and read file using pickle

We first used the pickle.dump() method to write the employees dictionary to the employees.txt file and then used the pickle.Unpickler() class to read the pickle data stream.

# Make sure you haven't opened the file in `wb` mode by mistake

A common cause of the error is opening the file in wb or w mode by mistake.

The w (write) or wb (write binary) modes truncate the file before opening it.

In other words, if you open the file in wb mode, its contents are deleted.

If you then try to open the file in rb (read binary) mode, it will be empty which will cause the "Pickle EOFError: Ran out of input" error.

For example, suppose you have the following code sample.

main.py

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import pickle

file_path = 'employees.txt'

employees = {
    'name': ['Alice', 'Bobby Hadz', 'Carl'],
    'age': [29, 30, 31]
}

with open(file_path, 'wb') as employees_file:
    employee_data = pickle.load(employees_file)

The code sample causes the io.UnsupportedOperation: not readable error because we opened the file in wb mode by mistake.

The wb mode truncates the file (deletes its contents) and is used for writing binary data to the file.

Instead, the rb (read binary) mode should be used for reading the file as we did in the previous subheading.

If the pickled file might be empty, you have to make sure that its size is greater than 0 bytes before reading from it.

main.py

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import os
import pickle

file_path = 'employees.txt'

if os.path.getsize(file_path) > 0:
    with open(file_path, 'rb') as my_file:
        unpickler = pickle.Unpickler(my_file)
        employee_data = unpickler.load()
        print(employee_data)
else:
    print('The file is empty')

check if file is empty before using pickle

# Handing the `EOFError` exception in a try/except block

You can also solve the error by using a try/except block.

main.py

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import pickle

file_path = 'employees.txt'

employee_data = {}

try:
    with open(file_path, 'rb') as my_file:
        unpickler = pickle.Unpickler(my_file)
        employee_data = unpickler.load()
        print(employee_data)
except EOFError:
    print('An EOFError exception occurred. The file is empty')

using try except block to handle error

We placed the with open statement in a try block.

If an error occurs, the except block is run.

Using the with open() statement should be your preferred approach over using open() directly because the file is closed even if an error occurs.

The except block is run if an EOFError is raised in the try block.

If an EOFError exception is raised, then the pickled file is empty and you need to handle the exception as you see fit.

For example, you could write to the file as we did in the first subheading.

Alternatively, you can set the outer scope variable to a default value in the except block.

main.py

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import pickle

file_path = 'employees.txt'

employee_data = {}

try:
    with open(file_path, 'rb') as my_file:
        unpickler = pickle.Unpickler(my_file)
        employee_data = unpickler.load()
        print(employee_data)
except EOFError:
    print('An EOFError exception occurred. The file is empty')
    employee_data = {}

# A working example that uses the open() function directly

The previous examples used the with open() statement, however, you can also use the open() function directly.

main.py

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import pickle

file_path = 'employees.txt'

employees = {
    'name': ['Alice', 'Bobby Hadz', 'Carl'],
    'age': [29, 30, 31]
}

file_path = 'employees.txt'

file_output = open(file_path, 'wb')
pickle.dump(employees, file_output)
file_output.close()

file_input = open(file_path, 'rb')
data = pickle.load(file_input)

# 👇️ {'name': ['Alice', 'Bobby Hadz', 'Carl'], 'age': [29, 30, 31]}
print(data)

print(type(data))  # <class 'dict'>

file_input.close()

using open function directly

We first opened the file in wb (write binary) mode and used the pickle.dump() method to write the dictionary to the file.

Make sure to close the file when using the open() function directly.

Otherwise, you'd have a memory leak in your application.

The next step is to open the file in rb (read binary) mode.

The pickle.load() method reads the pickled representation of the file.

# Additional Resources

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Pickle EOFError: Ran out of input in Python [Solved]