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https://github.com/svisser/pollywog
Syntactic sugar for working with regular expressions in Python.
https://github.com/svisser/pollywog
Last synced: 4 days ago
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Syntactic sugar for working with regular expressions in Python.
- Host: GitHub
- URL: https://github.com/svisser/pollywog
- Owner: svisser
- License: mit
- Created: 2014-12-31T15:22:29.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2014-12-31T15:27:51.000Z (almost 10 years ago)
- Last Synced: 2024-10-18T20:31:35.064Z (2 months ago)
- Language: Python
- Size: 107 KB
- Stars: 0
- Watchers: 3
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
Syntactic sugar for working with regular expressions in Python. Based on a [blog post](http://charlesleifer.com/blog/playing-with-python-magic-methods-to-make-a-nicer-regex-api/).
### Usage
In the following examples we will use these regular expressions to capture URLs:
```python
from pollywog import R
simple_url_re = '(https?://)([^/]+)(/[\S]*)?'
url_re = '(?Phttps?://)(?P[^/]+)(?P/[\S]*)?'
```
#### Checking if a match exists
```python
url = raw_input('Enter a URL: ')
if R/simple_url_re/url:
print 'You entered a valid URL'
else:
print 'That URL appears to be invalid.'
```
#### Extracting data from a match
The *rshift* `>>` operator will populate a dictionary or list with search results:
```python
# Store search results in the `results` dictionary.
result = {}
R/url_re/'http://charlesleifer.com/blog/'>>result
print result
# {'scheme': 'http://', 'host': 'charlesleifer.com', 'path': '/blog/'}
# Store search results in the `url_parts` list.
url_parts = []
R/url_re/'https://github.com/coleifer/'>>url_parts
print url_parts
# ['https://', 'github.com', '/coleifer/']
```
For less magic, you can also use the `search()` method. By default, the `search()` method will return a `tuple`.
```python
url = raw_input('Enter a URL: ')
result = (R/simple_url_re/url).search()
if result:
scheme, host, path = result
print 'Scheme:', scheme
print 'Host:', host
print 'Path:', path
```
By using named parameters, the `search()` method can also return a `dict`.
```python
url = raw_input('Enter a URL: ')
result = (R/url_re/url).search(as_dict=True)
if result:
print 'Scheme:', result['scheme']
print 'Host:', result['host']
print 'Path:', result['path']
```
#### Iterating over matches
The default iterator will return tuples:
```python
sample = """
This is a test. Visit http://charlesleifer.com/ for more examples.
Also check out my GitHub at https://github.com/coleifer/
"""
for scheme, host, path in R/url_re/sample:
print host + path
```
Though it is also possible to iterate over dictionaries:
```python
sample = """
This is a test. Visit http://charlesleifer.com/ for more examples.
Also check out my GitHub at https://github.com/coleifer/
"""
result = R/url_re/sample
for url_dict in result.iter_dicts():
print url_dict['host'] + url_dict['path']
```
#### Search and Replace
To perform a replacement, just tack on another slash followed by the replacement expression:
```python
print R/'(person)'/'hello person!'/'charlie'
# Prints: "hello charlie!"
print R/'(person)'/'I love you person!'/'baby huey'
# Prints: "I love you baby huey!"
```
Another example using references to capture-groups:
```python
# US phone number with area code, e.g. (555) 123-4567
phone_re = '\((\d{3})\)[-\s](\d{3})-(\d{4})'
# Normalize phone number to use dots.
replacement = r'\1.\2.\3'
print R/phone_re/'(555) 123-4567'/replacement
# Prints: 555.123.4567
```
#### Splitting strings
To split strings, use the subtraction operator:
```python
# Split on whitespace and non-alphanumeric.
rgx = '[\s\W]+'
print R/rgx-'hey! "testing 123"'
['hey', 'testing', '123', '']
```
For slightly less magic, you can also use the `split()` method:
```python
rgx = '[\s\W]+'
print (R/rgx/'hey! "testing 123"').split()
['hey', 'testing', '123', '']
```