python re.match example
python re.match example
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Python's re
module provides support for regular expressions (regex) - a sequence of characters that forms a search pattern, mainly for string manipulation. One of the most powerful and versatile tools in Python for working with text data.
Here are some examples:
import re
Simple Matching
phone_num = "123-456-7890"
pattern = r'd{3}-d{3}-d{4}'
match = re.match(pattern, phone_num)
print(match) # Output: <_sre.SRE_Match object; match='123-456-7890'>
Group Matching
phone_num = "123-456-7890"
pattern = r'(d{3})-(d{3})-(d{4})'
match = re.match(pattern, phone_num)
print(match.groups()) # Output: ('123', '456', '7890')
Multiple Matches
text = "hello world, hello python"
pattern = r'bhellob'
matches = re.finditer(pattern, text)
for match in matches:
print(match) # Output: Each match will be printed as a separate object
Non-Greedy Matching
text = "
This is a test
"
pattern = r'<[^>]*>'
match = re.search(pattern, text)
print(match.group()) # Output: '
', '
', '', 'a', ''
Positive Lookahead
text = "This is a test string"
pattern = r'test(?=.*string)'
match = re.search(pattern, text)
print(match) # Output: <_sre.SRE_Match object; match='test'>
Negative Lookbehind
text = "This is a test string"
pattern = r'(?<!test).*'
match = re.match(pattern, text, re.I)
print(match.group()) # Output: ' This is a '
These examples demonstrate various features of the re
module:
re.finditer
is the way to go. Non-Greedy Matching: If you want to match something as few times as possible, use non-greedy quantifiers like .*?
. Positive Lookahead: A positive lookahead asserts that a certain string will follow the current position in the text, without including it in your overall match. Negative Lookbehind: You can look behind the start of the match to ensure that you don't match something if it contains a certain pattern, for instance, "not preceded by test".
These are just a few examples of how powerful and versatile the re
module is.
Python re match
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