Python re.purge() Method
re.purge()is a Pythonremodule function used toclear regular expression cachefunction.
Python's re module caches compiled regular expression objects to improve performance,re.purge()can clear this cache.
Word Definition： purgemeans to clear, purge.
Basic Syntax and Parameters
Syntax Format
re.purge()
Parameter Description
- No parameters
Function Description
- Return Value: No return value.
- Function: Clears all compiled regular expressions cached internally by the re module.
Examples
Example 1: Basic Usage
Example
import re
# First use some regular expressions
re.search(r'\d+', '123')
re.match(r'\w+', 'hello')
# Clear the cache
re.purge()
print("Cache cleared")
# First use some regular expressions
re.search(r'\d+', '123')
re.match(r'\w+', 'hello')
# Clear the cache
re.purge()
print("Cache cleared")
Expected output:
Cache cleared
Example 2: Viewing Cache Effect
Example
import re
# Use the same pattern multiple times - cache will be used
for _ in range(3):
re.search(r'\d+', '123')
# Clear the cache
re.purge()
print("Cache cleared, it will be recreated afterwards")
re.search(r'\d+', '456')
# Use the same pattern multiple times - cache will be used
for _ in range(3):
re.search(r'\d+', '123')
# Clear the cache
re.purge()
print("Cache cleared, it will be recreated afterwards")
re.search(r'\d+', '456')
Expected output:
Cache cleared, and will be recreated afterwards
Example 3: Memory Release
Example
import re
import sys
# Create a large number of different regular expressions (will occupy cache)
patterns = [re.compile(r'\d+' + str(i)) for i in range(100)]
print(f"Created {len(patterns)} regular expressions")
# Clear the cache
re.purge()
print("Cache released")
import sys
# Create a large number of different regular expressions (will occupy cache)
patterns = [re.compile(r'\d+' + str(i)) for i in range(100)]
print(f"Created {len(patterns)} regular expressions")
# Clear the cache
re.purge()
print("Cache released")
Expected output:
创建了 100 个正则表达式 缓存已释放
Usage Scenario Description
- Use when memory needs to be released
- Use when regular expressions need to be reloaded after modification
- Periodically clean the cache in long-running programs
Other Extensions