Found 27104 Articles for Server Side Programming

GroupingWe group part of a regular expression by enclosing it in a pair of parentheses. This way we apply operators to the group instead of a single character.Capturing Groups and BackreferencesParentheses not only group sub-expressions but they also create backreferences. The part of the string matched by the grouped part of the regular expression, is stored in a backreference. With the use of backreferences we reuse parts of regular expressions. If sub-expression is placed in parentheses, it can be accessed with \1 or $1 and so on.For example, the regex \b(\w+)\b\s+\1\b matches repeated words, such as tahiti tahiti, because the parentheses ... Read More

The re.groups() methodThis method returns a tuple containing all the subgroups of the match, from 1 up to however many groups are in the pattern. The default argument is used for groups that did not participate in the match; it defaults to None.  In later versions (from 1.5.1 on), a singleton tuple is returned in such cases.example>>> m = re.match(r"(\d+)\.(\d+)", "27.1835") >>> m.groups() ('27', '1835')If we make the decimal place and everything after it optional, not all groups might participate in the match. These groups will default to None unless the default argument is given −>>> m = re.match(r"(\d+)\.?(\d+)?", "27") >>> m.groups()   ... Read More

We can build regular expressions that recognise repeated character groups using a few special characters. The following metacharacters can be used to search for a character or set of repeated characters. The question mark was the first repeating operator or quantifier developed. It effectively makes it optional by instructing the engine to try matching the previous token 0 or 1 times. The engine is instructed to try matching the previous token zero or more times by the asterisk or star. The plus instructs the engine to make one or more attempts to match the previous token. . Angle brackets are ... Read More

Regex, short for regular expression, is a powerful tool in Python that allows you to perform complex text pattern matching and manipulation. It's like a Swiss Army knife for string handling, enabling you to slice, dice, and reconfigure text with finesse. However, when it comes to matching characters after repetition, a common pitfall awaits the unwary coder. In this article, we'll delve into this challenge, exploring five distinct code examples, each accompanied by a step−by−step breakdown to illuminate the path through this regex thicket. Example We import the 're' module to access regex functionality. The pattern `r'(\d)+(?=x)'` is constructed. ... Read More

A single character can be matched in python with using regular expression. Regular expression is a sequence of characters that helps you to find a string or a set of string by using a search pattern. Regular expressions are also known as RegEx. Python provides the re module that is used to work with regular expression. In this article, we will look at how to match a single character in python using regular expression. We use ‘.’ special character to match any single character. Using findall() function In the following example, let us assume ‘oats cat pan’ as a string. ... Read More

The following are the differences between JavaScript and C++.JavaScript is a lightweight, interpreted programming language. It is designed for creating network-centric applications. It is complementary to and integrated with Java. JavaScript is very easy to implement because it is integrated with HTML. It is open and cross-platform.C++ is a middle-level programming language developed by Bjarne Stroustrup starting in 1979 at Bell Labs. It runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX.JavaScript is a scripting whereas C++ is a programming language.C++ program is to be compiled and executed, whereas a script in ... Read More

A regular expression is a group of characters that allows you to use a search pattern to find a string or a set of strings. RegEx is another name for regular expressions. The re module in Python is used to work with regular expressions. In this article we look how to extract non digit characters in python by using regular expression. We use \D+ regular expression in python to get non digit characters from a string. Where, \D returns a match that does not contain digits. + implies zero or more occurrences of characters. Using findall() function In ... Read More

There are two ways to match any one uppercase character in python using Regular Expression. One is the general method and other is using the regular expression. Using Regular Expression A regular expression is a series of characters that allows you to discover a string or a set of strings using a search pattern. Regular expressions are sometimes known as RegEx. In Python, the re module is used to work with regular expressions. In this article we will match the uppercase vowel in python using regular expression. To achieve this, we use r'[A, E, I, O, U]' regular expression. Here, ... Read More

There are two ways to match any one lowercase vowel in python using Regular Expression. One is the general method and other is using the regular expression. Using the general method In the following code, we have matched all the lowercase vowels from the string 'TutRoIals POinT Is A GreAt PlaTfOrm to lEarN '. Here, we did not use regular expression to match. We used the general method to match the lowercase vowels. Example The following example is a program which shows the matching of any one lowercase vowel in python using the general method. string='TutRoIals POinT Is A GreAt ... Read More

A regular expression is a series of characters that allows you to discover a string or a set of strings using a search pattern. Regular expressions are sometimes known as RegEx. In Python, the re module is used to work with regular expressions. We can use repetitions in regular expression to match the string in python. To make repetitions possible in regular expression, we indicate the number of times the character is repeating in {}. Using search() function In the following example, we match ‘TTTTPPP’ string which is present in the string ‘TTTTTTPPPPPPPPPPPP’. Here, we have used T{4}P{3} to match ... Read More