The re module | Python Fiddle

# File: re-example-1.py

import re

text = "The Attila the Hun Show"

# a single character
m = re.match(".", text)
if m: print repr("."), "=>", repr(m.group(0))

# any string of characters
m = re.match(".*", text)
if m: print repr(".*"), "=>", repr(m.group(0))

# a string of letters (at least one)
m = re.match("\w+", text)
if m: print repr("\w+"), "=>", repr(m.group(0))

# a string of digits
m = re.match("\d+", text)
if m: print repr("\d+"), "=>", repr(m.group(0))

# File: re-example-2.py

import re

text ="10/15/99"

m = re.match("(\d{2})/(\d{2})/(\d{2,4})", text)
if m:
    print m.group(1, 2, 3)

# File: re-example-3.py

import re

text = "Example 3: There is 1 date 10/25/95 in here!"

m = re.search("(\d{1,2})/(\d{1,2})/(\d{2,4})", text)

print m.group(1), m.group(2), m.group(3)

month, day, year = m.group(1, 2, 3)
print month, day, year

date = m.group(0)
print date
# File: re-example-4.py

import re

text = "you're no fun anymore..."

# literal replace (string.replace is faster)
print re.sub("fun", "entertaining", text)

# collapse all non-letter sequences to a single dash
print re.sub("[^\w]+", "-", text)

# convert all words to beeps
print re.sub("\S+", "-BEEP-", text)

# File: re-example-5.py

import re
import string

text = "a line of text\\012another line of text\\012etc..."

def octal(match):
    # replace octal code with corresponding ASCII character
    return chr(string.atoi(match.group(1), 8))

octal_pattern = re.compile(r"\\(\d\d\d)")

print text
print octal_pattern.sub(octal, text)

# File: re-example-6.py

import re, string

def combined_pattern(patterns):
    p = re.compile(
        string.join(map(lambda x: "("+x+")", patterns), "|")
        )
    def fixup(v, m=p.match, r=range(0,len(patterns))):
        try:
            regs = m(v).regs
        except AttributeError:
            return None # no match, so m.regs will fail
        else:
            for i in r:
                if regs[i+1] != (-1, -1):
                    return i
    return fixup

#
# try it out!

patterns = [
    r"\d+",
    r"abc\d{2,4}",
    r"p\w+"
]

p = combined_pattern(patterns)

print p("129391")
print p("abc800")
print p("abc1600")
print p("python")
print p("perl")
print p("tcl")

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