Javascript string match specific regex

Question

I want to match specific string from this variable.

var string = '150-50-30-20=50+skip50-20-10-5=15+1*2*3*4=24+50-50*30*20=0+skip2*4*8=64';

Here is my regex :

var string = '150-50-30-20=50+skip50-20-10-5=15+1*2*3*4=24+50-50*30*20=0+skip2*4*8=64';

var match_data = [];

match_data = string.match(/[0-9]+(?:((\s*\-\s*|\s*\*\s*)[0-9]+)*)\s*\=\s*[0-9]+(?:(\s*\+\s*[0-9]+(?:((\s*\-\s*|\s*\*\s*)[0-9]+)*)\s*=\s*[0-9]+)*)/g);

console.log(match_data);

The output will show

[
   0: "150-50-30-20=50"
   1: "50-20-10-5=15+1*2*3*4=24+50-50*30*20=0"
   2: "2*4*8=64"
]

The result that I want to match from string variable is only

 [
     0: "150-50-30-20=50"
     1: "1*2*3*4=24"
     2: "50-50*30*20=0"
 ]

You may use /(\+skip)?(\d+(?:\s*[-*]\s*\d+)*\s*=\s*\d+)/gi and whenever Group 1 is not undefined, skip/omit that match, else, grab Group 2 value. See this JS demo. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented May 13, 2019 at 11:08
With ECMAScript 2018 compliant environments, you may use match_data = string.match(/(?<!\+skip)\d+(?:\s*[-*]\s*\d+)*\s*=\s*\d+/gi) — Wiktor Stribiżew
– Wiktor Stribiżew, Commented May 13, 2019 at 11:14
@evolutionxbox No idea, probably it is an answer. I am just not sure about the actual requirement. If something works, it is not necessarily the answer. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented May 13, 2019 at 11:15

Wiktor Stribiżew · Accepted Answer · 2019-05-13 11:39:52Z

2

You may use ((?:\+|^)skip)? capturing group before (\d+(?:\s*[-*\/+]\s*\d+)*\s*=\s*\d+) in the pattern, find each match, and whenever Group 1 is not undefined, skip (or omit) that match, else, grab Group 2 value.

var string = '150-50-30-20=50+skip50-20-10-5=15+1*2*3*4=24+50-50*30*20=0+skip2*4*8=64', 
 reg = /((?:^|\+)skip)?(\d+(?:\s*[-*\/+]\s*\d+)*\s*=\s*\d+)/gi,
 match_data = [], 
 m;
while(m=reg.exec(string)) {
   if (!m[1]) {
      match_data.push(m[2]);
   }
}
console.log(match_data);

Note that I added / and + operators ([-*\/+]) to the pattern.

Regex details

((?:^|\+)skip)? - Group 1 (optional): 1 or 0 occurrences of +skip or skip at the start of a string
(\d+(?:\s*[-*\/+]\s*\d+)*\s*=\s*\d+) - Group 2:
- \d+ - 1+ digits
- (?:\s*[-*\/+]\s*\d+)* - zero or more repetitions of
  - \s*[-*\/+]\s* - -, *, /, + enclosed with 0+ whitespaces
  - \d+ - 1+ digits
- \s*=\s* - = enclosed with 0+ whitespaces
- \d+ - 1+ digits.

edited May 13, 2019 at 11:39

answered May 13, 2019 at 11:26

Wiktor Stribiżew

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2 Comments

Willyanto Halim Over a year ago

when i moved skip50-20-10-5=15 and the string will become var string = 'skip50-20-10-5=15+1*2*3*4=24+150-50-30-20=50+50-50*30*20=0+skip2*4*8=64'; it didn't work

Wiktor Stribiżew Over a year ago

@WillyantoHalim Easy fix, use reg = /((?:^|\+)skip)?(\d+(?:\s*[-*\/+]\s*\d+)*\s*=\s*\d+)/gi

Pushpesh Kumar Rajwanshi · Accepted Answer · 2019-05-13 12:32:14Z

2

As per your input string and the expected results in array, you can just split your string with + and then filter out strings starting with skip and get your intended matches in your array.

const s = '150-50-30-20=50+skip50-20-10-5=15+1*2*3*4=24+50-50*30*20=0+skip2*4*8=64'
console.log(s.split(/\+/).filter(x => !x.startsWith("skip")))

There are other similar approaches using regex that I can suggest, but the approach mentioned above using split seems simple and good enough.

answered May 13, 2019 at 12:32

Pushpesh Kumar Rajwanshi

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Comments

Kamil Kiełczewski · Accepted Answer · 2019-05-13 11:15:07Z

0

try

var t = string.split('+skip');
var tt= t[1].split('+');
var r = [t[0],tt[1],tt[2]]

var string = '150-50-30-20=50+skip50-20-10-5=15+1*2*3*4=24+50-50*30*20=0+skip2*4*8=64';

var t = string.split('+skip');
var tt= t[1].split('+');
var r = [t[0],tt[1],tt[2]]

console.log(r)

edited May 13, 2019 at 11:15

answered May 13, 2019 at 11:09

Kamil Kiełczewski

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4 Comments

Willyanto Halim Over a year ago

this answer is only for 1 situation.. i want the code will run dynamically in any condition.

Kamil Kiełczewski Over a year ago

@WillyantoHalim you not desciribe desired output - describe it and give more examples in question

Willyanto Halim Over a year ago

as you saw this post was about regex.. so i want to exclude it from regex.

Kamil Kiełczewski Over a year ago

@WillyantoHalim so you don't know what do you want on output? - regexp descibe wrong result so it is not good source of information what do you want

Pablo · Accepted Answer · 2019-05-13 12:25:36Z

0

const string = '150-50-30-20=50+skip50-20-10-5=15+1*2*3*4=24+50-50*30*20=0+skip2*4*8=64';
const stepOne = string.replace(/skip[^=]*=\d+./g, "")
const stepTwo = stepOne.replace(/\+$/, "")
const result = stepTwo.split("+")
console.log(result)

answered May 13, 2019 at 12:25

Pablo

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