Match anything other than a lowercase vowel Regular Expression Examples Literal characters Sr.No. Otherwise refers to the octal representation of a character code. Matches nth grouped subexpression if it matched already. Matches newlines, carriage returns, tabs, etc. Matches backspace (0x08) when inside brackets. Matches word boundaries when outside brackets. If a newline exists, it matches just before newline. Matches independent pattern without backtracking. Specifies position using pattern negation. Temporarily toggles off i, m, or x options within parentheses. Temporarily toggles on i, m, or x options within parentheses. Groups regular expressions without remembering matched text. If in parentheses, only that area is affected. Temporarily toggles off i, m, or x options within a regular expression. Temporarily toggles on i, m, or x options within a regular expression. Groups regular expressions and remembers matched text. Matches at least n and at most m occurrences of preceding expression. Matches n or more occurrences of preceding expression. Matches exactly n number of occurrences of preceding expression. Matches 0 or 1 occurrence of preceding expression. Matches 1 or more occurrence of preceding expression. Matches 0 or more occurrences of preceding expression. Matches any single character not in brackets Matches any single character in brackets. Using m option allows it to match newline as well. Matches any single character except newline. You can escape a control character by preceding it with a backslash.įollowing table lists the regular expression syntax that is available in Python − Sr.No. * ^ $ ( ) | \), all characters match themselves. It ignores whitespace (except inside a set or when escaped by a backslash) and treats unescaped # as a comment marker.Įxcept for control characters, ( ?. Permits "cuter" regular expression syntax. This flag affects the behavior of \w, \W, \b, \B. Interprets letters according to the Unicode character set. Makes a period (dot) match any character, including a newline. Makes $ match the end of a line (not just the end of the string) and makes ^ match the start of any line (not just the start of the string). This interpretation affects the alphabetic group (\w and \W), as well as word boundary behavior(\b and \B). Interprets words according to the current locale. You can provide multiple modifiers using exclusive OR (|), as shown previously and may be represented by one of these − Sr.No. The modifiers are specified as an optional flag. Regular expression literals may include an optional modifier to control various aspects of matching. Regular Expression Modifiers: Option Flags When the above code is executed, it produces the following result − We use group(num) or groups() function of match object to get matched expression. The re.search function returns a match object on success, none on failure. This is the string, which would be searched to match the pattern anywhere in the string. This function searches for first occurrence of RE pattern within string with optional flags. When the above code is executed, it produces following result − This method returns all matching subgroups in a tuple (empty if there weren't any) This method returns entire match (or specific subgroup num) The re.match function returns a match object on success, None on failure. These are modifiers, which are listed in the table below. You can specify different flags using bitwise OR (|). This is the string, which would be searched to match the pattern at the beginning of string. This is the regular expression to be matched. Here is the description of the parameters − Sr.No. This function attempts to match RE pattern to string with optional flags. To avoid any confusion while dealing with regular expressions, we would use Raw Strings as r'expression'. But a small thing first: There are various characters, which would have special meaning when they are used in regular expression. We would cover two important functions, which would be used to handle regular expressions. The re module raises the exception re.error if an error occurs while compiling or using a regular expression. The Python module re provides full support for Perl-like regular expressions in Python. Regular expressions are widely used in UNIX world. A regular expression is a special sequence of characters that helps you match or find other strings or sets of strings, using a specialized syntax held in a pattern.
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