How to split a string on pattern of one or more repeating character and retain match?

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For example, get a string abaacaaa, a character a, split the string to get ['ab', 'aac', 'aaa'].

string = 'abaacaaa'
string.split('a')      // 1. ["", "b", "", "c", "", "", ""]
string.split(/(?=a)/)  // 2. ["ab", "a", "ac", "a", "a", "a"]
string.split(/(?=a+)/) // 3. ["ab", "a", "ac", "a", "a", "a"]

string.split(/*???*/)  // 4. ['ab', 'aac', 'aaa']

Why is 3rd expression outputs the same value as 2nd even if + presented after a, and what to put into 4th?


string.match(/a+[^a]*/g) doesn't work properly in babaacaaa.

string = 'babaacaaa'     // should be splited to ['b', 'ab', 'aac', 'aaa']
string.match(/a+[^a]*/g) // ["ab", "aac", "aaa"]

Solutions 2 and 3 are equal because unanchored lookaheads test each position in the input. string. (?=a) tests the start of string in abaacaaa, and finds a match, the leading empty result is discarded. Next, it tries after a, no match since the char to the right is b, the regex engine goes on to the next position. Next, it matches after b. ab is added to the result. Then it matches a position after a, adds a to the resulting array, and goes to the next position to find a match. And so on. With (?=a+) the process is indetical, it just matches 1+ as, but still tests each position.

To split babaacaaa, you need

var s = 'babaacaaa';

Repeating a Capturing Group vs. Capturing a Repeated Group, Repeating a capturing group in a regular expression is not the same as Only these two are possible, and you want to capture the abc or 123 to figure out which group #1 was entered between the 4th and 5th characters in the string. does preserve backtracking information for capturing groups after the match attempt.). split() is a string function in Perl which is used to split or you can say to cut a string into smaller sections or pieces. There are different criteria to split a string, like on a single character, a regular expression (pattern), a group of characters or on undefined value etc..

let string = 'abaacaaa'
let result = string.match(/a*([^a]+|a)/g)

string = 'babaacaaa'
result = string.match(/a*([^a]+|a)/g)

[PDF] Regular Expressions: The Complete Tutorial, a programmer, you can save yourself lots of time and effort. You can often word grey in one operation, instead of two. There are many A "match" is the piece of text, or sequence of bytes or characters that pattern was found to Repeating Character Classes myString.split("regex") splits the string at each regex match. A more convenient way is to specify how many repetitions of each character we want using the curly braces notation. For example, a{3} will match the a character exactly three times. Certain regular expression engines will even allow you to specify a range for this repetition such that a{1,3} will match the a character no more than 3 times, but no less than once for example.

string.match(/^[^a]+|a+[^a]*/g) seems to work as expected.

Wireless Communication And Sensor Network, The method of divide and conquer is always more effective in big data analysis of the data', to effectively save network bandwidth resources and calculation resources. and they proposed one new and fast character string matching algorithm, string of the original matching segment is repeated within the pattern string,  Splits the string in the Series/Index from the beginning, at the specified delimiter string. Equivalent to str.split (). pat : str, optional. String or regular expression to split on. If not specified, split on whitespace. n : int, default -1 (all) Limit number of splits in output. None, 0 and -1 will be interpreted as return all splits.

Regular Expression HOWTO, You can also use REs to modify a string or to split it apart in various ways. If the regex pattern is a string, \w will match all the characters marked as letters Another repeating metacharacter is +, which matches one or more times. If you'​re accessing a regex within a loop, pre-compiling it will save a few  Any string containing three digits, a hyphen, and four more digits would return a true value for IsMatch. You can combine the repeat quantifier with any valid literal or escape character. With minor adjustments, you can create a regular expression that will match U.S. phone number values, with or without an area code.

From Bash to Z Shell: Conquering the Command Line, not split into separate words that can be sorted. This allows us to use a separator character of our choosing. saw for some glob qualifiers in the section “More Complicated Qualifiers: String Arguments” in Chapter 9. allow you to repeat an operation on every line oftheir input, pattern operators, when used with an array,  Thus, the regular expression matches any substring consisting of one or more spaces. The split() method here is basically a convenience routine built upon this pattern matching behavior; more fundamental is the match() method, which will tell you whether the beginning of a string matches the pattern:

Split strings at delimiters - MATLAB split, If str is a string array or cell array of character vectors, and has multiple elements, newStr , matches ] = split(___) additionally returns an array, matches , that contains all When split divides on repeated delimiters, it returns empty strings as  Capturing Groups. If the pattern includes two or more parenthesis, then the end result will be a tuple instead of a list of string, with the help of parenthesis () group mechanism and finall (). Each pattern matched is represented by a tuple and each tuple contains group (1), group (2).. data. Live Demo.

  • By what context you expect the string to get splitted?
  • I want to rotate a string to be minimum laxicographically. E.g From abaca to aabac
  • Unanchored lookaheads test each position in the input string. Hence, 2 = 3. Also, 'abaacaaa'.match(/a+[^a]*/g) seems to work as 4).
  • In python you could also use lookbehinds to find the position you asked for to perform a split operation (e.g. ^|(?<=[^a])(?=a+(?:[^a]|$)) but unfortunately lookbehinds are not supported by javascript at the moment. Check: