REGEX
Regex Module in Vint
The regex module in Vint provides powerful functionality to perform regular expression operations like matching patterns, replacing strings, and splitting strings. Regular expressions are useful for text processing and pattern matching.
Importing the Regex Module
To use the Regex module, import it as follows:
import regex
Functions and Examples
1. Matching a Pattern with match
The match function checks if a string matches a specified pattern. It returns true if the string matches the pattern and false if it does not.
Syntax:
match(pattern, string)
pattern: The regular expression pattern.string: The string to match against the pattern.
Example:
import regex result = regex.match("^Hello", "Hello World") print(result) // Expected output: true
In this case, the string starts with "Hello", so it matches the pattern.
2. Using match to Check Non-Matches
You can use match to check if a string does not match a given pattern. If the pattern is not found at the beginning of the string, it will return false.
Example:
import regex result = regex.match("^World", "Hello World") print(result) // Expected output: false
Since the string does not start with "World", the result is false.
3. Replacing Part of a String with replaceString
The replaceString function replaces parts of a string that match a pattern with a new value.
Syntax:
replaceString(pattern, replacement, string)
pattern: The regular expression pattern.replacement: The string to replace the matched part with.string: The input string.
Example:
import regex newString = regex.replaceString("World", "VintLang", "Hello World") print(newString) // Expected output: "Hello VintLang"
In this case, "World" is replaced by "VintLang", resulting in "Hello VintLang".
4. Splitting a String with splitString
The splitString function splits a string into a list of substrings based on a regular expression pattern.
Syntax:
splitString(pattern, string)
pattern: The regular expression pattern used as a delimiter.string: The string to be split.
Example:
import regex words = regex.splitString("\\s+", "Hello World VintLang") print(words) // Expected output: ["Hello", "World", "VintLang"]
Here, \\s+ matches one or more whitespace characters, so the string is split into words.
5. Splitting a String by a Comma
You can also split a string by a specific delimiter, such as a comma, using splitString.
Example:
import regex csv = regex.splitString(",", "apple,banana,orange") print(csv) // Expected output: ["apple", "banana", "orange"]
The string "apple,banana,orange" is split at each comma.
6. Matching a Complex Pattern
You can match more complex patterns, such as an email address, using match with a regex pattern.
Example:
import regex emailMatch = regex.match("^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$", "test@example.com") print(emailMatch) // Expected output: true
This pattern matches valid email addresses, so "test@example.com" matches successfully.
7. Replacing Digits in a String
You can use replaceString to replace parts of a string that match a pattern, such as replacing digits with asterisks.
Example:
import regex maskedString = regex.replaceString("\\d", "*", "My phone number is 123456789") print(maskedString) // Expected output: "My phone number is *********"
Here, \\d matches any digit, so the digits in the phone number are replaced with asterisks.
Summary of Functions
| Function | Description | Example Output |
|---|---|---|
match(pattern, string) | Checks if the string matches the given pattern. | true or false |
replaceString(pattern, replacement, string) | Replaces parts of a string matching a pattern with a new value. | A modified string |
splitString(pattern, string) | Splits a string into a list of substrings based on the pattern. | List of substrings |
The regex module is extremely useful for text manipulation, pattern matching, and string processing tasks in Vint. Whether you need to validate input, split strings, or replace parts of a string, the regex module provides powerful tools to handle these tasks efficiently.