Regex to Get String Between Curly Braces

Regex to get string between curly braces

If your string will always be of that format, a regex is overkill:

>>> var g='{getThis}';
>>> g.substring(1,g.length-1)
"getThis"

substring(1 means to start one character in (just past the first {) and ,g.length-1) means to take characters until (but not including) the character at the string length minus one. This works because the position is zero-based, i.e. g.length-1 is the last position.

For readers other than the original poster: If it has to be a regex, use /{([^}]*)}/ if you want to allow empty strings, or /{([^}]+)}/ if you want to only match when there is at least one character between the curly braces. Breakdown:

/: start the regex pattern
- {: a literal curly brace
  - (: start capturing
    - [: start defining a class of characters to capture
      - ^}: "anything other than }"
    - ]: OK, that's our whole class definition
    - *: any number of characters matching that class we just defined
  - ): done capturing
- }: a literal curly brace must immediately follow what we captured
/: end the regex pattern

Regex: Get anything between any curly braces

You may get the results you need using

var results = Regex.Matches(text, @"{({*[^{}]*}*)}")
        .Cast<Match>()
        .Select(x => x.Groups[1].Value);

See the regex demo.

Regex details

{ - an open curly brace
({*[^{}]*}*) - Group 1:
- {* - 0 or more open curly braces
- [^{}]* - 0 or more chars other than curly braces
- }* - 0 or more close curly braces
} - a close curly brace

regex - extract strings between curly braces without the curly braces

We can use a regex lookaround to match the { as lookaround followed by one or more characters that are not a }.

stringr::str_extract(text_test, '(?<=\\{)[^\\}]+')
#[1] "function_name"  "function_title" "function_name"

Regex matches one or more characters that are not a } ([^\\}]+) that follows a { (regex lookaround ((?<=\\{))

In base R, we can use regmatches/regexpr

regmatches(text_test, regexpr("(?<=\\{)[^\\}]+", text_test, perl = TRUE))
#[1] "function_name"  "function_title" "function_name"

Regex to get string between curly bracket tags in PHP

You need to escape the braces, and use /s to match more than single line. Below is the code example.

Code

<?php

$input = '
{list:start:Data}
   {id} is having a title of {title}
{list:end:Data}

{list:start:Data1}
   {id1} is having a title of {title1}
{list:end:Data1}

{list:start:Data2}
   {id2} is having a title of {title2}
{list:end:Data2}

{list:start:Data3}
   {id3} is having a title of {title3}
{list:end:Data3}

';

preg_match_all(
    "/\\{list:start:(.+?)\\}(.*?)\\{list:end:(.+?)\\}/s",
    $input,
    $preg_matches
);

$matches = [];
foreach ($preg_matches[1] as $k => $v) {
    $matches[] = [
        "string" => trim($v),
        "data" => trim($preg_matches[2][$k])
    ];
}

print_r($matches);

Output

Array
(
    [0] => Array
        (
            [string] => Data
            [data] => {id} is having a title of {title}
        )

    [1] => Array
        (
            [string] => Data1
            [data] => {id1} is having a title of {title1}
        )

    [2] => Array
        (
            [string] => Data2
            [data] => {id2} is having a title of {title2}
        )

    [3] => Array
        (
            [string] => Data3
            [data] => {id3} is having a title of {title3}
        )

)

Regex to match string between curly braces (that allows to escape them via 'doubling')

You can use

(?<!{)(?:{{)*{([^{}]*)}(?:}})*(?!})

See the .NET regex demo.

In C#, you can use

var results = Regex.Matches(text, @"(?<!{)(?:{{)*{([^{}]*)}(?:}})*(?!})").Cast<Match>().Select(x => x.Groups[1].Value).ToList();

Alternatively, to get full matches, wrap the left- and right-hand contexts in lookarounds:

(?<=(?<!{)(?:{{)*{)[^{}]*(?=}(?:}})*(?!}))

See this regex demo.
In C#:

var results = Regex.Matches(text, @"(?<=(?<!{)(?:{{)*{)[^{}]*(?=}(?:}})*(?!}))")
    .Cast<Match>()
    .Select(x => x.Value)
    .ToList();

Regex details

(?<=(?<!{)(?:{{)*{) - immediately to the left, there must be zero or more {{ substrings not immediately preceded with a { char and then {
[^{}]* - zero or more chars other than { and }
(?=}(?:}})*(?!})) - immediately to the right, there must be }, zero or more }} substrings not immediately followed with a } char.

Regex: find string between curly brackets, which itself contains curly brackets

If there is no arbitrary nesting, you can use a pattern with negated }{ like

\\hyperlink{[^}{]*}{[^}{]*(?:{[^}{]*}[^}{]*)*}

Similar this answer but unrolled. See the demo at regex101. To {extract} use groups (demo).

Depending on your environment / regex flavor it can be necessary to escape the opening { by a backslash for the braces that are not inside a character class to match them literally.

Further note that \S+ can consume } and .+ can match more than desired if unaware.

Extract string between curly braces in java

There is an indexOf method that takes the index from which to search

String str = "{a,b,c},{1,2,3}";
int startingIndex = str.indexOf("{");
int closingIndex = str.indexOf("}");
String result1 = str.substring(startingIndex + 1, closingIndex);
System.out.println(result1);

startingIndex = str.indexOf("{", closingIndex + 1);
closingIndex = str.indexOf("}", closingIndex + 1);
String result2 = str.substring(startingIndex + 1, closingIndex);
System.out.println(result2);

In the second block, we make the search start at closingIndex + 1 where closingIndex is the index of the last seen }.

Regular expression between curly braces, but ignore nested

This is a job for recursion.

If your regex flavour supports it, you can use:

(?<={)([^{}]++|\{(?1)\})+(?=})

Demo & explanation

Regex pattern to get string between curly braces

You can use this recursive regex pattern in PHP:

$re = '/( { ( (?: [^{}]* | (?1) )* ) } )/x'; 
$str = "The quick brown {fox, dragon, dinosaur} jumps over the lazy {dog, cat, bear, {lion, tiger}}."; 

preg_match_all($re, $str, $matches);
print_r($matches[2]);

RegEx Demo

Regex to Get String Between Curly Braces