AttributeError: 'NoneType' object has no attribute 'group'

# AttributeError: 'NoneType' object has no attribute 'group'

The Python "AttributeError: 'NoneType' object has no attribute" occurs when we try to call the group() method on a None value, e.g. after calling match() or search() with no matches.

To solve the error, use an if statement before calling group.

Here is a very simple example of how the error occurs.

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example = None

# ⛔️ AttributeError: 'NoneType' object has no attribute 'group'
example.group()

Trying to access or set an attribute on a None value causes the error.

# A function that doesn't return anything returns None

The most common source of a None value (other than an explicit assignment) is a function that doesn't return anything.

For example, the re.match() and re.search() methods return None if there are no matches.

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import re

# 👇️ None
m = re.match(r"(\w+) (\w+)", "hello")

# ⛔️ AttributeError: 'NoneType' object has no attribute 'group'
print(m.group())

Since the string does not match the pattern, the match() method returns None.

# Using a try/except statement to avoid getting the error

One way to solve the error is to use a try/except statement.

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import re

a_string = 'bobby hadz com'

try:
    matches = re.match(r"(\w+) (\w+)", a_string).group()
except AttributeError:
    matches = re.match(r"(\w+) (\w+)", a_string)

print(matches)  # 👉️ bobby hadz

If the string doesn't match the pattern, the re.match() method returns None and accessing the group() method on a None value causes an AttributeError exception.

In this case, the except block runs where we don't call the group() method.

# Check if the value is not None before calling group()

You can get around this by using an if statement to check if there are matches before calling group().

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import re

m = re.match(r"(\w+) (\w+)", "hello")

if m:
    print(m.group())
else:
    print('There are no matches') # 👉️ this runs

You could also be more explicit in the if statement and check that the m variable is not None.

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import re

m = re.match(r"(\w+) (\w+)", "hello")

if m is not None:
    print(m.group())
else:
    print('There are no matches')

# The re.search() method possibly returns None

The re.search() method also returns None if no position in the string matches the pattern.

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import re

# 👇️ None
m = re.search('(?<=abc)def', 'xyz')

# ⛔️ AttributeError: 'NoneType' object has no attribute 'group'
print(m.group(0))

You can use the same approach to only call the group method if there was a match.

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import re

m = re.search('(?<=abc)def', 'abcdef')

if m is not None:
    print(m.group())  # 👉️ def
else:
    print('There are no matches')

The if block is only run if the m variable is not None, otherwise the else block runs.

# The Match.groups() method possibly returns None

The same is the case when using the Match.groups method.

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import re

# 👇️ none
m = re.match(r"(\d+)\.(\d+)", "hello")

# ⛔️ AttributeError: 'NoneType' object has no attribute 'groups'
print(m.groups())

The Match.groups method returns None if there are no matches and a default argument is not provided.

To get around the error, use a simple if statement.

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import re

# 👇️ none
m = re.match(r"(\d+)\.(\d+)", "123.456")

if m is not None:
    print(m.groups())  # 👉️ ('123', '456')
else:
    print('There are no matches')

The "AttributeError: 'NoneType' object has no attribute 'group'" occurs for multiple reasons:

1. Having a function that doesn't return anything (returns None implicitly).
2. Explicitly setting a variable to None.
3. Assigning a variable to the result of calling a built-in function that doesn't return anything.
4. Having a function that only returns a value if a certain condition is met.