How to modify the regex

Question

I have a text as below and some words and their meanings are included in the text.I need to get these words using a Javascript regex method. For example, if I give below text than return words should be Necessity, Lay of the land, and Mumble.

Necessity:(noun)the need for something, or something that is needed Example: In my work, a computer is a necessity.

Lay of the land: (idiom n. Or v.)the general state or condition of affairs under consideration; the facts of a situation Example: We asked a few questions to get the lay of the land

Mumble:(verb) to speak quietly or in an unclear way so that the words are difficult to understand Example: She mumbled something about needing to be home, then left.

I have coded as below but it doesn't work as expected.

let text = `Necessity:(noun)the need for something, or something that is needed
Example: In my work, a computer is a necessity.

Lay of the land: (idiom n. Or v.)the general state or condition of affairs under consideration; the facts of a situation
Example: We asked a few questions to get the lay of the land.

Mumble:(verb) to speak quietly or in an unclear way so that the words are difficult to understand
Example: She mumbled something about needing to be home, then left.
`;

let matches = text.match(/[A-Za-z]+(?=\:\S)/g);

console.log(matches); //['Necessity', 'Mumble']

May I know what am I missing? Any help would be appreciated.

anubhava · Accepted Answer · 2022-12-09 10:04:28Z

3

You may use this regex:

/^[A-Za-z]+(?:\s+[A-Za-z]+)*(?=:)/gm

RegEx Demo

RegEx Breakdown:

^: Start
[A-Za-z]+: Match 1+ of English letters
(?:\s+[A-Za-z]+)*: Match 1+ whitespaces followed by 1+ of English letters. Repeat this group 0 or more times.
(?=:): Lookahead to assert that we have : at next position

answered Dec 9, 2022 at 10:04

anubhava

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Comments

Tim Biegeleisen · Accepted Answer · 2022-12-09 10:07:45Z

Try this version:

let text = `Necessity:(noun)the need for something, or something that is needed
Example: In my work, a computer is a necessity.

Lay of the land: (idiom n. Or v.)the general state or condition of affairs under consideration; the facts of a situation
Example: We asked a few questions to get the lay of the land.

Mumble:(verb) to speak quietly or in an unclear way so that the words are difficult to understand
Example: She mumbled something about needing to be home, then left.
`;

let matches = text.match(/(^|(?<=\n\n))\w+(?: \w+)*(?=:)/g);

console.log(matches);

Here is an explanation of the regex pattern used:

(
- ^ the start of the string
- | OR
- (?<=\n\n) lookbehind and assert two newlines precede
)
\w+ match a word
(?: \w+)* followed by space and another word, zero or more times
(?=:) assert that : follows this word or words

Jostein S · Accepted Answer · 2022-12-09 10:21:22Z

I like my Regex's as short as possible so here's my take.

const text = `Necessity:(noun)the need for something, or something that is needed Example: In my work, a computer is a necessity.

Lay of the land: (idiom n. Or v.)the general state or condition of affairs under consideration; the facts of a situation Example: We asked a few questions to get the lay of the land

Mumble:(verb) to speak quietly or in an unclear way so that the words are difficult to understand Example: She mumbled something about needing to be home, then left.`;

let matches = text.match(/^\S[^:]+/gm);
console.log(matches);

Breakdown:

^ asserts start of line
\S matches any non-whitespace character.
[^:]+ matches all character which isn't : one or unlimited times.

Houssem Cherif · Accepted Answer · 2022-12-09 10:25:34Z

0

You can do it as above:

let regex_exp = /(^|(?<=\n\n))\w+(?: \w+)*(?=:)/g;
let matches = text.match(regex_exp);
console.warn(matches);

answered Dec 9, 2022 at 10:25

Houssem Cherif

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1 Comment

Cihat Şaman Over a year ago

Your answer looks below answer. stackoverflow.com/a/74741597/7901430 What's different?

The fourth bird · Accepted Answer · 2022-12-09 13:18:00Z

In your pattern [A-Za-z]+(?=\:\S) you are not matching any spaces in case of multiple words, and you are asserting a colon to the right followed by a non whitespace char using (?=\:\S)

If there should be a part with a colon and parenthesis following and using a capture group:

^([A-Za-z].*?):\s*\([^()]*\)

Explanation

^ Start of string
([A-Za-z].*?) Capture group 1, match a char A-Za-z followed by any char except a newline, as least as possible
:\s* Match a colon and optional whitespace chars
\([^()]*\) Match from (...)

See a regex demo.

const regex = /^([A-Za-z].*?):\s*\([^()]*\)/gm;
const str = `Necessity:(noun)the need for something, or something that is needed Example: In my work, a computer is a necessity.

Lay of the land: (idiom n. Or v.)the general state or condition of affairs under consideration; the facts of a situation Example: We asked a few questions to get the lay of the land

Mumble:(verb) to speak quietly or in an unclear way so that the words are difficult to understand Example: She mumbled something about needing to be home, then left.`;

const result = Array.from(str.matchAll(regex), m => m[1]);
console.log(result);

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