Match can be easy or very complex. For simple match we can use function in str. For sophisticated match, we can use regex or other external libraries.
we could simply using endswith, startswith function in the string to check suffix or prefix
just_len = 55
filename = 'spam.txt'
print('whether filename ends with .txt'.ljust(just_len),
filename.endswith('.txt'))
url = 'http://www.python.org'
print('whether url starts with http:'.ljust(just_len),
url.startswith('http:'))
if we want check match with multiple choices then just provide a tuple with all those choices
import os
python_files = [filename for filename in os.listdir('.') if filename.endswith(('.py', '.pyc'))]
print('get all file match .py or .pyc'.ljust(just_len),
python_files)
using following expression to check if there is any file which the filename end with '.py'
print('if there is any file ends with .py'.ljust(just_len),
any(name.endswith('.py') for name in os.listdir('.')))
'any' could be treated as more powerful match compare to 'in' 'in' check the whole object, while any could using functions
print('if there is string_match.py'.ljust(just_len),
'string_match.py' in os.listdir('.'))
print('if there is string_match.py'.ljust(just_len),
any(name == 'string_match.py' for name in os.listdir('.')))
we can use find to check whether and where is the substring located it will return position or -1 if not exist
text = 'yeah, but no, but yeah, but no, but yeah'
print('find "no" '.ljust(just_len), text.find('no'))
print('rfind "no"'.ljust(just_len), text.rfind('no'))
the following test will be the same to check if the substring existed
print('whether "what" in text'.ljust(just_len),
'what' in text)
print('whether "what" in text using find'.ljust(just_len),
text.find('what') != -1)
the following match using shell wildcard matching depends on OS, like on Windows, foo.txt is the same with FOO.TXT which means 'foo.txt' will match '*.TXT' on windows but it will not match on Unix like system
from fnmatch import fnmatch
print('whether foo.txt matches *.txt'.ljust(just_len),
fnmatch('foo.txt', '*.txt'))
print('whether foo.txt matches *.TXT'.ljust(just_len),
fnmatch('foo.txt', '*.TXT'))
the following match always case sensitive
from fnmatch import fnmatchcase
print('whether foo.txt match *.txt case sensitive'.ljust(just_len),
fnmatchcase('foo.txt', '*.txt'))
print('whether foo.txt match *.TXT case sensitive'.ljust(just_len),
fnmatchcase('foo.txt', '*.TXT'))
using regex to match a date it will either return a match object or None
import re
date_pattern = re.compile(r'\d+/\d+/\d+') # <digit>/<digit>/<digit>
print('11/27/2012 match to pattern'.ljust(just_len),
date_pattern.match('11/27/2012'))
print('Nov 27, 2012 match to matter'.ljust(just_len),
date_pattern.match('Nov 27, 2012'))
if not a match from start, then it will return None but the suffix does not matter
print('Today is 11/27/2012. PyCon starts 3/13/2013. match'.ljust(just_len),
date_pattern.match('Today is 11/27/2012. PyCon starts 3/13/2013.'))
print('11/27/2012. PyCon starts 3/13/2013. match'.ljust(just_len),
date_pattern.match('11/27/2012. PyCon starts 3/13/2013.'))
if want test with complete match, then add a $ in the pattern
print('11/27/2012 complete match',
re.match(r'\d+/\d+/\d+$', '11/27/2012'))
print('11/27/2012. PyCon starts 3/13/2013. complete match',
re.match(r'\d+/\d+/\d+$', '11/27/2012. PyCon starts 3/13/2013.'))
we could find all matches. find all return a list
print('find all date'.ljust(just_len),
date_pattern.findall('Today is 11/27/2012. PyCon starts 3/13/2013.'))
to test whether a patter existed in a string we could using finditer which will return a generator and tested using 'any' there will be no list created, and will not doing further match if already found
print('find whether there is a date'.ljust(just_len),
any(date_pattern.finditer('Today is 11/27/2012. PyCon starts 3/13/2013.')))
we could match with groups
pattern_with_group = re.compile(r'(\d+)/(\d+)/(\d+)')
match = pattern_with_group.match('11/27/2012')
print('match get groups at once'.ljust(just_len),
match.groups())
group(0) is the complete match and consequence is each sub group
print('match get groups separately'.ljust(just_len),
match.group(0), match.group(1), match.group(2), match.group(3))
text = 'UPPER PYTHON, lower python, Mixed Python'
print('find all python case insensitive'.ljust(just_len),
re.findall('python', text, flags=re.IGNORECASE))
print('where there is python case insensitive'.ljust(just_len),
any(re.finditer('python', text, flags=re.IGNORECASE)))
print('by default re using greedy match'.ljust(just_len),
re.findall(r'\"(.*)\"', 'Computer says "no." Phone says "yes."'))
print('add ? after * makes match none greedy '.ljust(just_len),
re.findall(r'\"(.*?)\"', 'Computer says "no." Phone says "yes."'))
multiline_comments = '''/* this is a
...
multiline comment */
this will not be included*/
... '''
match /
print('by default match does not across new lines'.ljust(just_len),
re.findall(r'/\*(.*?)\*/', multiline_comments))
print('re.DOTALL means . matches all include new lines'.ljust(just_len),
re.findall(r'/\*(.*?)\*/', multiline_comments, re.DOTALL))
match /
print('((?:.|\\n) to specify include new line'.ljust(just_len),
re.findall(r'/\*((?:.|\n)*?)\*/', multiline_comments))
print("[?:.|\\n] does not working(don't why)".ljust(just_len),
re.findall(r'/\*[.|\n]*?\*/', multiline_comments))