# import re

**[import re](https://docs.python.org/3/library/re.html)** is a Python import that provides regular expression matching. Use it to search, match, replace, or split strings based on patterns.

## Example

```python
# Python
# description: regex matching, substitution, splitting

import re

text = "Contact: alice@example.com or bob@test.org"

# Find all email addresses
emails = re.findall(r"\b[a-z]+@[a-z.]+\b", text)
print(emails)  # ['alice@example.com', 'bob@test.org']

# Check if pattern matches
if re.search(r"@example\.com", text):
    print("Found example.com address")

# Replace pattern
result = re.sub(r"@\S+", "@hidden", text)
print(result)  # Contact: alice@hidden or bob@hidden

# Split by pattern
parts = re.split(r"[,:]", "one,two:three")
print(parts)  # ['one', 'two', 'three']

# Compiled regex for repeated use
pattern = re.compile(r"\d+")
numbers = pattern.findall("Page 1, 2, 3")
print(numbers)  # ['1', '2', '3']
```

## Common functions

- `re.search(pattern, text)`: find first match
- `re.match(pattern, text)`: match at start of string
- `re.findall(pattern, text)`: find all matches
- `re.sub(pattern, repl, text)`: replace matches
- `re.split(pattern, text)`: split by pattern
- `re.compile(pattern)`: create reusable regex object
- `pattern.finditer(text)`: iterate over matches with position