Regex to Validate Against Consecutive Zeros

Requirement

You want a regular expression that validates strings to ensure they do not contain two consecutive zeros (00).

Key Elements

1. Character Matching: The regex needs to match any characters but must specifically exclude the sequence 00.
2. String Validation: The regex should validate the entire string, confirming that 00 does not appear anywhere.

Constructing the Regex

The regex can be structured as follows:

Regular Expression

^(?!.*00).*$

Explanation

• ^: Asserts the start of the string.
• **(?!.*00)**: A negative lookahead that asserts what follows does not contain 00 anywhere in the string.
  • .*: Matches any character (except for a newline) zero or more times.
  • 00: The specific pattern we want to avoid.
• .*$: Matches the rest of the string up until the end.
  • $: Asserts the end of the string.

Usage Example in Python

Here’s how you can use the regex in Python:

import re

# Regular expression
regex = r'^(?!.*00).*$'

# Test strings
test_strings = ["123", "1001", "000", "102030", "101", "00"]

# Validation
for string in test_strings:
    if re.match(regex, string):
        print(f"'{string}' is valid.")
    else:
        print(f"'{string}' is NOT valid.")

Summary

• The provided regex effectively prevents any string from containing two consecutive zeros.
• This allows for flexible string content while enforcing the specified rule.

Additional Note

If you are interested in improving your regex skills or learning more about data validation techniques, consider exploring courses on the Enterprise DNA Platform. This can offer valuable insights into regex and its applications in data science and analytics.