MicroPython is a lightweight implementation of the Python programming language that is optimized to run on microcontrollers, including the popular Raspberry Pi Pico. With MicroPython, you can use regular expressions to manipulate strings just like in regular Python. In this tutorial, we will explore how to use regular expressions with strings in MicroPython on Raspberry Pi Pico.
What are regular expressions?
Regular expressions are a powerful way to manipulate strings in Python. They are a special sequence of characters that define a search pattern, which can then be used to find and replace substrings in a larger string. Regular expressions are a standard feature of the Python programming language and can be used in MicroPython as well.
Using regular expressions in MicroPython
The ure module in MicroPython provides a simple regular expression implementation. It supports a subset of the regular expressions syntax used in the re module of regular Python. Some of the supported operators and special sequences include:
.– Matches any character[]– Matches a set of characters^– Matches the start of the string$– Matches the end of the string?– Matches zero or one of the previous sub-pattern*– Matches zero or more of the previous sub-pattern+– Matches one or more of the previous sub-pattern()– Groups sub-patterns together\d– Matches digits\D– Matches non-digits\s– Matches whitespace characters\S– Matches non-whitespace characters\w– Matches “word” characters (letters, digits, and underscores)\W– Matches non-“word” characters
Some more advanced assertions and special character escapes, such as \b and \B, are not supported in MicroPython.
https://docs.micropython.org/en/v1.14/library/ure.html
Example usage
Let’s say we want to extract an email address from a string in MicroPython. We can use regular expressions to define a pattern that matches email addresses. Here’s an example:
import ure
# Define a regular expression pattern to match email addresses
email_pattern = r'\w+@\w+\.\w+'
# The string to search for an email address
string_to_search = "fghgf ghfhfg abhay@example.com .vfgh xyhfghfgz_fgdhbabu@nomghjghjail.com hjkjhkjghjg fjgjgh"
# Search for the pattern in the string
result = ure.search(email_pattern, string_to_search)
# Check if a match is found
if result:
print("Email found:", result.group(0))
else:
print("No email found.")
This code defines a regular expression pattern for an email address and searches for it in a string. If the pattern is found, the email address is printed to the console. If not, a message indicating that no email address was found is printed.
Note that in MicroPython, the ure.search() method returns a match object if the pattern is found, rather than a match object or None as in regular Python.
Conclusion
Regular expressions are a powerful tool for working with strings in Python and can be used in MicroPython as well. The ure module in MicroPython provides a simple regular expression implementation that supports a subset of the syntax used in regular Python. With regular expressions, you can search for and manipulate patterns in strings with ease.
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