split()
split() — метод разбивает строку на массив строк используя для этого заданный разделитель.
Синтаксис
separator — условие по которому будет разделена строка. В качестве разделителя может выступать строковый литерал или регулярное выражение. Также можно использовать специальные символы, например перевод строки, кавычки или юникод. Параметр является необязательным.
limit — количество элементов, которые должен вернуть метод. Параметр необязательный, если пропустить в массив попадут все подстроки. Если задать, то split() все-равно разделит всю строку по разделителям, но возвратит только указанное количество.
При нахождении разделителя метод удаляет separator и возвращает подстроку.
Если задать в качестве разделителя пустое значение » , тогда каждый символ строки запишется в отдельный элемент массива.
Если при записи split() пропустить separator , то метод вернет массив с одним элементом, который будет содержать всю строку.
Разбить строку по разделителю
Результатом будет массив с двумя элементами: Native JavaScript и React
Разбить строку на символы
Здесь мы разделили строку myDream с помощью split(») , задав в качестве separator пустое значение. Все это записали в allSymbols — теперь там массив, где каждый элемент это символ нашей строки. Далее используя цикл for вывели в console все символы — каждый с новой строки.
Разбить строку используя регулярное выражение
/,|-/ в этом регулярном выражении мы указали разделители, которые необходимо учесть — запятая и дефис. В итоге получаем массив, где перечислены все языки программирования указанные изначально.
Вывести символы строки в обратном порядке
Для того, чтобы решить эту задачу нам понадобятся еще два метода reverse() и join() . Первый перевернет массив, а второй объединит элементы в строку. В итоге получим в console JavaScript, HTML, CSS, TypeScript, React
Сумма элементов массива
Выполняя подобные задачи стоит помнить, что метод split() записывает данные в массив в формате строки, поэтому перед тем, как складывать элементы необходимо сначала привести их к числу. Здесь это сделано с помощью + перед выражением. Также можно воспользоваться функцией Number(numForSum[n]) .
Итого
1. Метод split() делит строку по разделителю и записывает все в массив.
2. В получившемся массиве, элементы хранятся в формате текст.
3. В параметрах метода, первым свойством задается разделитель, вторым ограничение на вывод элементов. Оба параметра не обязательны.
Как разделить массив на символы
Time complexity : O(n)
Auxiliary Space: O(n)
In C++
Method 1: Using stringstream API of C++
Prerequisite: stringstream API
Stringstream object can be initialized using a string object, it automatically tokenizes strings on space char. Just like “cin” stream stringstream allows you to read a string as a stream of words. Alternately, we can also utilise getline function to tokenize string on any single character delimiter.
The code below demonstrates it.
Method 2: Using C++ find() and substr() APIs.
This method is more robust and can parse a string with any delimiter, not just spaces(though the default behavior is to separate on spaces.) The logic is pretty simple to understand from the code below.
Method 3: Using temporary string
If you are given that the length of the delimiter is 1, then you can simply use a temp string to split the string. This will save the function overhead time in the case of method 2.
Time complexity : O(n)
Auxiliary Space: O(n)
In Java :
In Java, split() is a method in String class.
Output:
Time complexity : O(n)
Auxiliary Space: O(1)
In Python:
The split() method in Python returns a list of strings after breaking the given string by the specified separator.
Python3
Output:
Time Complexity : O(N), since it just traverse through the string finding all whitespace.
Auxiliary Space : O(1), since no extra space has been used.
explode
Returns an array of strings, each of which is a substring of string formed by splitting it on boundaries formed by the string separator .
Parameters
The boundary string.
The input string.
If limit is set and positive, the returned array will contain a maximum of limit elements with the last element containing the rest of string .
If the limit parameter is negative, all components except the last — limit are returned.
If the limit parameter is zero, then this is treated as 1.
Note:
Prior to PHP 8.0, implode() accepted its parameters in either order. explode() has never supported this: you must ensure that the separator argument comes before the string argument.
Return Values
Returns an array of string s created by splitting the string parameter on boundaries formed by the separator .
If separator is an empty string (""), explode() throws a ValueError . If separator contains a value that is not contained in string and a negative limit is used, then an empty array will be returned, otherwise an array containing string will be returned. If separator values appear at the start or end of string , said values will be added as an empty array value either in the first or last position of the returned array respectively.
Changelog
| Version | Description |
|---|---|
| 8.0.0 | explode() will now throw ValueError when separator parameter is given an empty string ( "" ). Previously, explode() returned false instead. |
Examples
Example #1 explode() examples
<?php
// Example 1
$pizza = «piece1 piece2 piece3 piece4 piece5 piece6» ;
$pieces = explode ( » » , $pizza );
echo $pieces [ 0 ]; // piece1
echo $pieces [ 1 ]; // piece2
// Example 2
$data = «foo:*:1023:1000::/home/foo:/bin/sh» ;
list( $user , $pass , $uid , $gid , $gecos , $home , $shell ) = explode ( «:» , $data );
echo $user ; // foo
echo $pass ; // *
Example #2 explode() return examples
<?php
/*
A string that doesn’t contain the delimiter will simply
return a one-length array of the original string.
*/
$input1 = «hello» ;
$input2 = «hello,there» ;
$input3 = ‘,’ ;
var_dump ( explode ( ‘,’ , $input1 ) );
var_dump ( explode ( ‘,’ , $input2 ) );
var_dump ( explode ( ‘,’ , $input3 ) );
The above example will output:
Example #3 limit parameter examples
// positive limit
print_r ( explode ( ‘|’ , $str , 2 ));
// negative limit
print_r ( explode ( ‘|’ , $str , — 1 ));
?>
String.prototype.split()
The split() method takes a pattern and divides a String into an ordered list of substrings by searching for the pattern, puts these substrings into an array, and returns the array.
Try it
Syntax
Parameters
The pattern describing where each split should occur. Can be undefined , a string, or an object with a Symbol.split method — the typical example being a regular expression. Omitting separator or passing undefined causes split() to return an array with the calling string as a single element. All values that are not undefined or objects with a @@split method are coerced to strings.
A non-negative integer specifying a limit on the number of substrings to be included in the array. If provided, splits the string at each occurrence of the specified separator , but stops when limit entries have been placed in the array. Any leftover text is not included in the array at all.
- The array may contain fewer entries than limit if the end of the string is reached before the limit is reached.
- If limit is 0 , [] is returned.
Return value
An Array of strings, split at each point where the separator occurs in the given string.
Description
If separator is a non-empty string, the target string is split by all matches of the separator without including separator in the results. For example, a string containing tab separated values (TSV) could be parsed by passing a tab character as the separator, like myString.split(«\t») . If separator contains multiple characters, that entire character sequence must be found in order to split. If separator appears at the beginning (or end) of the string, it still has the effect of splitting, resulting in an empty (i.e. zero length) string appearing at the first (or last) position of the returned array. If separator does not occur in str , the returned array contains one element consisting of the entire string.
If separator is an empty string ( «» ), str is converted to an array of each of its UTF-16 «characters», without empty strings on either ends of the resulting string.
Note: «».split(«») is therefore the only way to produce an empty array when a string is passed as separator .
Warning: When the empty string ( «» ) is used as a separator, the string is not split by user-perceived characters (grapheme clusters) or unicode characters (codepoints), but by UTF-16 codeunits. This destroys surrogate pairs. See «How do you get a string to a character array in JavaScript?» on StackOverflow.
If separator is a regexp that matches empty strings, whether the match is split by UTF-16 code units or Unicode codepoints depends on if the u flag is set.
If separator is a regular expression with capturing groups, then each time separator matches, the captured groups (including any undefined results) are spliced into the output array. This behavior is specified by the regexp’s Symbol.split method.
If separator is an object with a Symbol.split method, that method is called with the target string and limit as arguments, and this set to the object. Its return value becomes the return value of split .
Any other value will be coerced to a string before being used as separator.
Examples
Using split()
When the string is empty and a non-empty separator is specified, split() returns [«»] . If the string and separator are both empty strings, an empty array is returned.
The following example defines a function that splits a string into an array of strings using separator . After splitting the string, the function logs messages indicating the original string (before the split), the separator used, the number of elements in the array, and the individual array elements.
This example produces the following output:
Removing spaces from a string
In the following example, split() looks for zero or more spaces, followed by a semicolon, followed by zero or more spaces—and, when found, removes the spaces and the semicolon from the string. nameList is the array returned as a result of split() .
This logs two lines; the first line logs the original string, and the second line logs the resulting array.
Returning a limited number of splits
In the following example, split() looks for spaces in a string and returns the first 3 splits that it finds.
Splitting with a RegExp to include parts of the separator in the result
If separator is a regular expression that contains capturing parentheses ( ) , matched results are included in the array.
Note: \d matches the character class for digits between 0 and 9.
Using a custom splitter
An object with a Symbol.split method can be used as a splitter with custom behavior.
The following example splits a string using an internal state consisting of an incrementing number:
The following example uses an internal state to enforce certain behavior, and to ensure a «valid» result is produced.