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128 lines
3.1 KiB
Python
128 lines
3.1 KiB
Python
# Examples for using Python's Regular expression module "re"
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# sr 11/30/2013
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import re
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'''OVERVIEW
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'*' matches all characters that follow (0 or more)
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'+' matches all characters that follow (1 or more)
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'?' makes the previous character optional
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'{4}' previous character must match exactly 4 times
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'{2-4}' previous character must match exactly 2-4 times
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'[0-9]' matches all characters in the set of numbers 0 to 9
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'[A-Z]' matches all characters in the set of A to Z
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'\d' matches all digits, e.g., '4', '9' ...
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'\D' matches all NON-digit characters
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'\s' matches all space characters: '', '\t', '\r', '\n'
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'\S' matches all NON-space characters
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'\w' matches all non-punctuation characters (i.e., letters and digits)
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'\W' matches all NON-letter and NON-digit characters
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'^bla' NOT-matches 'bla'
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'let$' matches 'let' but not 'letter'
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'\b' matches transition between non-word characters and word characters
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'''
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data = '''2013-01-01
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2012-02-02
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aaaa-02-02
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aa-02-02
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-04-04
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2000 02-02
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ghi stu
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2012-03-03'''.strip().split('\n')
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# A >> '*' matches all characters that follow (0 or more)
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print (50*'-' + '\nA\n' + 50*'-')
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for line in data:
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match = re.search('(.*)-(..)-(..)', line) # note the parantheses
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if match:
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print(match.group(1), match.group(2), match.group(3))
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'''
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--------------------------------------------------
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A
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--------------------------------------------------
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2013 01 01
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2012 02 02
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aaaa 02 02
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aa 02 02
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04 04
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2012 03 03
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'''
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# B >> '+' matches all characters that follow (1 or more)
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print (50*'-' + '\nB\n' + 50*'-')
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for line in data:
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match = re.search('(.+)-(..)-(..)', line) # note the parantheses
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if match:
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print(match.group(1), match.group(2), match.group(3))
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'''
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--------------------------------------------------
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B
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--------------------------------------------------
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2013 01 01
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2012 02 02
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aaaa 02 02
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aa 02 02
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2012 03 03
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'''
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# C >> '?' makes the previous character optional
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print (50*'-' + '\nC\n' + 50*'-')
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for line in data:
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match = re.search('(.+)-?(..)-(..)', line) # note the parantheses
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if match:
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print(match.group(1), match.group(2), match.group(3))
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'''
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--------------------------------------------------
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C
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--------------------------------------------------
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2013- 01 01
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2012- 02 02
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aaaa- 02 02
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aa- 02 02
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- 04 04
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2000 02 02
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2012- 03 03
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'''
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# D >> '{4}' previous character must match exactly 4 times
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print (50*'-' + '\nD\n' + 50*'-')
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for line in data:
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match = re.search('(a{4})-(..)-(..)', line) # note the parantheses
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if match:
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print(match.group(1), match.group(2), match.group(3))
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'''
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--------------------------------------------------
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D
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--------------------------------------------------
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aaaa 02 02
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'''
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# E >>'{2-4}' previous character must match exactly 2-4 times
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print (50*'-' + '\nE\n' + 50*'-')
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for line in data:
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match = re.search('(a{2,4})-(..)-(..)', line) # note the parantheses
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if match:
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print(match.group(1), match.group(2), match.group(3))
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'''
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--------------------------------------------------
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E
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--------------------------------------------------
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aaaa 02 02
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aa 02 02
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'''
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