I need a pattern that

Matches:

• 1
• 1, 4-5
• 1, 4-5, 8, 11, 13-14

Not Matches:

• 1,,,,

• 1, 4-5-

• 1, 4--------2233-----,,,,

I have tried a pattern but it doesn't work:-

1. /^(\d-\d,?|\d*,?)*$/g

and

1. /^(\d-{1}\d,?|\d*,?)*$/g

React code for allowing input in the particular pattern

  const customPageInputChange = (e) => {
    if(e.target.value.match(/(need a pattern)/) !== null) {
      setCustomPage(e.target.value)
    }
  }

I have referred many links but in StackOverflow but doesn't match Can anyone give a solution that matches the above pattern

Please try here https://jsfiddle.net/mayankshukla5031/4zqwq1fj/ If the pattern match let me know

CodePudding user response：

One possible regex:

^(\d (-\d )?, )*\d (-\d )?$

See https://regex101.com/r/txVh3e/1 for test cases or the following JavaScript demo:

const regex = /^(\d (-\d )?, )*\d (-\d )?$/;
const patterns = [
  '1',
  '1, 4-5',
  '1, 4-5, 8, 11, 13-14',
  '1,,,,',
  ', 4-5-',
  ', 4--------2233-----,,,,',
  '1, 2, 3, 4, 5',
];
for (const pattern of patterns) {
  if (pattern.match(regex)) {
    console.log(`'${pattern}' is valid`);
  } else {
    console.log(`'${pattern}' is invalid`);
  }
}

If you also want to check whether the pages are increasing, a regex is not really suitable, and you should opt for checking the strings programmatically.

CodePudding user response：

You might use

^\d (?:-\d )?(?:,\s*\d (?:-\d )?)*$

In Javascript you can use regex.test(str) to return a boolean to see if the pattern matched.

In parts, the pattern matches:

• ^ Start of string
• \d Match 1 digits
• (?:-\d )? Optionally match - and 1 digits
• (?: Non capture group to match as a whole part
  • ,\s* Match a comma and optional whitespace chars
  • \d (?:-\d )? The same as previous pattern
• )* Close the non capture group and optionally repeat to als match a single occurrence
• $ End of string

See a Regex demo