NameError: name 're' is not defined in Python

NameError: name 're' is not defined in Python #

The Python "NameError: name 're' is not defined" occurs when we use the re module without importing it first. To solve the error, import the re module before using it - import re.

Here is an example of how the error occurs.

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# ⛔️ NameError: name 're' is not defined
prog = re.compile(r'\w+')

result = prog.match('hello world 123')

print(result)

To solve the error, we have to import the re module.

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# ✅ import re module first
import re

prog = re.compile(r'\w+')

result = prog.match('hello world 123')

print(result)

Even though the re module is in the Python standard library, we still have to import it before using it.

Also, make sure you haven't imported re in a nested scope, e.g. a function. Import the module at the top level to be able to use it throughout your code.

An alternative to importing the entire re module is to import only the functions and constants that your code uses.

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# 👇️ import only compile function from re module
from re import compile

prog = compile(r'\w+')

result = prog.match('hello world 123')

print(result)

The example shows how to only import the compile function from the re module.

Instead of accessing the members on the module, e.g. re.compile, we now access them directly.

This should be your preferred approach because it makes your code easier to read.

Conversely, when we import specific functions, it is much easier to see which functions from the re module are being used.

The re module provides regular expression matching operations.

You can view all of the functions the re module provides by visiting the official docs.

Conclusion #

The Python "NameError: name 're' is not defined" occurs when we use the re module without importing it first. To solve the error, import the re module before using it - import re.