JavaScript - How to Match Multiple Parts of a String Using RegExp?

In JavaScript, the regular expression (RegExp) object provides a powerful mechanism to search, match, and manipulate strings. One of the common use cases is matching multiple parts of a string that satisfy a certain pattern. You can easily do this using global (g) and other RegExp features.

1. Using Global (g) Flag to Match Multiple Occurrences

The g flag enables global matching, which allows the regular expression to match all occurrences of a pattern in the string, not just the first one.

let s = "apple orange apple banana apple";
let regex = /apple/g;
let res = s.match(regex);

console.log(res);

[ 'apple', 'apple', 'apple' ]

• /apple/g matches the word "apple" globally.
• The match() method returns an array of all matched parts of the string.

2. Using match() with Capture Groups

You can use parentheses () to define capture groups in a regular expression. This allows you to match and extract multiple parts of the string that satisfy different conditions.

let s = "apple123 orange456 apple789";
let regex = /(\w+)(\d+)/g;
let res = [...s.matchAll(regex)];

console.log(res);  

[
  [
    'apple123',
    'apple12',
    '3',
    index: 0,
    input: 'apple123 orange456 apple789',
    groups: undefined
  ],
  [
    'orange456',
    'orange45',
    '6',
    index: 9,
    input: ...

• (\w+) matches the word characters (letters) and (\d+) matches digits.
• matchAll() returns all matches as an array of arrays, where each sub-array contains the full match and the captured groups.

3. Using exec() with Global Flag

The exec() method allows you to find multiple matches one at a time. It returns an array for each match, and with the global flag, it can be used in a loop to find all matches.

let s = "apple123 orange456 apple789";
let regex = /(\w+)(\d+)/g;
let ress;
while ((res = regex.exec(s)) !== null) {
    console.log(res);
}

[
  'apple123',
  'apple12',
  '3',
  index: 0,
  input: 'apple123 orange456 apple789',
  groups: undefined
]
[
  'orange456',
  'orange45',
  '6',
  index: 9,
  input: 'apple123 orange456 apple789',
...

• regex.exec(s) finds one match at a time, and with each iteration, it returns the full match and the captured groups.
• The while loop continues until all matches are found.

4. Using split() to Split String by Multiple Parts

The split() method can be used with a regular expression to break a string into multiple parts. If the regular expression matches multiple segments, the split() method will break the string accordingly.

let s = "apple123 orange456 apple789";
let regex = /\d+/g;
let res = s.split(regex);

console.log(res); 

[ 'apple', ' orange', ' apple', '' ]

• /\d+/g matches sequences of digits.
• split() breaks the string wherever a match is found, returning an array of non-matching parts.

5. Using Non-Capturing Groups to Match Multiple Patterns

Non-capturing groups (?:...) allow you to combine multiple patterns without creating separate capturing groups. This is useful when you need to match multiple patterns in a string but don’t need to extract the individual parts.

let s = "apple123 orange456 apple789";
let regex = /(?:apple|orange)\d+/g;
let res = s.match(regex);

console.log(res);

[ 'apple123', 'orange456', 'apple789' ]

• (?:apple|orange) matches either "apple" or "orange".
• \d+ matches one or more digits after "apple" or "orange".
• The g flag ensures all matching parts are found in the string.

6. Matching Multiple Patterns with OR (|) Operator

The | (OR) operator in regular expressions allows you to match one pattern or another. This can be used to match multiple parts of a string that satisfy different conditions.

let s = "apple orange123 banana456";
let regex = /apple|orange\d+/g;
let res = s.match(regex);

console.log(res);

[ 'apple', 'orange123' ]

• /apple|orange\d+/g matches either "apple" or "orange" followed by one or more digits.
• The g flag ensures that all matches are found in the string.

amansingla

Follow

Improve

Article Tags :

• JavaScript
• Web Technologies
• JavaScript-RegExp
• JavaScript-Questions