Regular expressions in one of the important topic in python. It is widely used by developer and testers. If you want to play around with data. One should know regular expressions.
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Regular expressions can be used to check if a string contains the specified search pattern.
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Regular expressions are used to remove the unnecessary words
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It also helps in finding out the correctness of the data and even operations such as finding, replacing and formatting the data is possible using Regular Expressions
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any single character
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(a|b)
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a or b
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[abc]
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Range (a or b or c)
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[^abc]
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Not (a or b or c)
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[a-z]
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Lower case letter from a to z
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[A-Z] Upper case letter from A to Z
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Upper case letter from A to Z
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[0-10]
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Digit from 0 to10
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\x
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Group/subpattern number "x"
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\
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Escape following character
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\Q
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Begin literal sequence
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\E
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End literal sequence
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?=
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Lookahead assertion
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?!
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Negative lookahead
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?<=
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Lookbehind assertion
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?!= or ?<!
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Negative lookbehind
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?>
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Once-only Subexpression
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?()
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Condition [if then]
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?()|
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Condition [if then else]
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?#
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Comment
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import re
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string = """I am Sourabh and my mobile no is 9479864026"""
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regex = '\d+'
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match = re.findall(regex, string)
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print(match)
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^
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Start of string, or start of line in multi-line pattern
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\A
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Start of string
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$
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End of string, or end of line in multi-line pattern
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\Z
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End of string
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\b
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Word boundary
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\B
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Not word boundary
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\<
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Start of word
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\>
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End of word
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\c
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Control character
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\s
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White space
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\S
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Not white space
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\d
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Digit
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\D
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Not digit
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\w
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Word
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\W
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Not word
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\x
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Hexadecimal digit
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\O
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Octal digit
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g
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Global match
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i *
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Case-insensitive
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m *
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Multiple lines
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s *
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Treat string as single line
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x *
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Allow comments and whitespace in pattern
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e *
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Evaluate replacement
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U *
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Ungreedy pattern
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import re
phone = "MY phone is +91-9479-86-40-26r"
# Remove anything other than digits
num = re.sub(r'\D', "", phone)
print ("Phone Num : ", num)
output Phone num : 9479864026|
*
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0 or more
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{5}
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exactly 5
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+
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1 or more
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{5,}
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5 or more
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?
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0 or 1
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{1,5}
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1,2,3,4 or 5
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\n
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New line
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\r
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Carriage return
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\t
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Tab
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\v
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Vertical tab
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\f
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Form feed
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\xxx
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Octal character xxx
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\xhh
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Hex character hh
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$`
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Before matched string
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$'
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After matched string
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+
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Last matched string
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$&
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Entire matched string
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import repattern = '^a...s$' test_string = 'abyss' result = re.match(pattern, test_string) if result: print("Search successful.") else: print("Search unsuccessful.")
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$`
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Before matched string
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$'
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After matched string
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+
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Last matched string
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$&
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Entire matched string
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[:upper:]
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Upper case letters
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[A-Z]
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[:lower:]
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lower case letter
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[a-z]
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[:alpha:]
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alphabets
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[a-zA-Z]
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[:alnum:]
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alphanumeric
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[a-zA-z0-9]
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[:digit:]
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Digits
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[0-9]
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[:xdigit:]
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Hexadecimal
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[A-Fa-f0-9]
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[:punct:]
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Punctuation
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[!"\#$%&'()*+, \-./:;<=>?@\[ \\\]^_‘{|}~]
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[:blank:]
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Space and tab
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[:space:]
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Blank characters
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[:cntrl:]
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Control characters
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[:graph:]
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Printed characters
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[:print:]
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Printed characters and spaces
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[:word:]
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Digits, letters and underscore
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