These regexes are equivalent (for matching purposes):
/^(7|8|9)\d{9}$//^[789]\d{9}$//^[7-9]\d{9}$/
The explanation:
(a|b|c)is a regex “OR” and means “a or b or c”, although the presence of brackets, necessary for the OR, also captures the digit. To be strictly equivalent, you would code(?:7|8|9)to make it a non capturing group.[abc]is a “character class” that means “any character from a,b or c” (a character class may use ranges, e.g.[a-d]=[abcd])
The reason these regexes are similar is that a character class is a shorthand for an “or” (but only for single characters). In an alternation, you can also do something like (abc|def) which does not translate to a character class.
Related Posts:
- OR condition in Regex
- Using or ‘|’ in regex [duplicate]
- What is a Context Free Grammar?
- What does \’.- mean in a Regular Expression
- How can I exclude one word with grep?
- How can I validate an email address using a regular expression?
- Regular expression to match a line that doesn’t contain a word
- Difference between \b and \B in regex
- Regex: ignore case sensitivity
- What does the regex \S mean in JavaScript?
- How can I validate an email address using a regular expression?
- Python regex AttributeError: ‘NoneType’ object has no attribute ‘group’
- Regular Expression for alphanumeric and underscores
- What is the difference between the regular expressions [^\d\s] and [\D\S]
- Regular Expression for alphanumeric and underscores
- grep –ignore-case –only
- Regex AND operator
- python re.split() to split by spaces, commas, and periods, but not in cases like 1,000 or 1.50
- python re.split() to split by spaces, commas, and periods, but not in cases like 1,000 or 1.50
- Regex to test if string begins with http:// or https://
- Regular expression negative lookahead
- Regular Expression to match string starting with a specific word
- Regular Expressions: Is there an AND operator?
- Regular expression to match standard 10 digit phone number
- Regular Expression.how to add optional character at end of regex
- Regular Expression with wildcards to match any character
- What is a non-capturing group in regular expressions?
- Split string on whitespace in Python
- How to validate an email address in PHP
- What is a non-capturing group in regular expressions?
- Regular expression to match standard 10 digit phone number
- How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
- Python string.replace regular expression
- How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
- Python string.replace regular expression
- Symbol for any number of any characters in regex?
- Grep and Python
- Regex – Does not contain certain Characters
- How to replace ” \ ” with ” \\ ” in java
- A regular expression to exclude a word/string
- Regex how to match an optional character
- How to validate an email address in JavaScript
- Using Bash regex match (=~) where regex includes quotes (” characters)
- Regular expression to match a word or its prefix
- How can I remove punctuation from input text in Java?
- Regular expression for exact match of a string
- Using the star sign in grep
- Regex optional group
- Regex for string contains?
- Regular Expression – Validate Gmail addresses
- Java; String replace (using regular expressions)?
- How can I remove punctuation from input text in Java?
- How can I output only captured groups with sed?
- How to negate specific word in regex?
- What is the grep equivalent in Python?
- javascript HTML from document.body.innerHTML
- Which regular expression operator means ‘Don’t’ match this character?
- Python re.split() vs split()
- Regex Explanation ^.*$ [duplicate]
- Negative matching using grep (match lines that do not contain foo)
- How to exclude a specific string constant?
- How to replace a whole line with sed?
- How to validate phone number using PHP?
- Validate phone number with JavaScript
- Can a URL contain a semicolon and still be valid?
- How is \\n and \\\n interpreted by the expanded regular expression?
- Regex to match only uppercase “words” with some exceptions
- Regular Expression to reformat a US phone number in Javascript
- Regex to match only letters
- Finding the complement of a DFA?
- RegEx to find two or more consecutive chars
- Regex to match an optional ‘+’ symbol followed by any number of digits
- Regular expressions in C: examples?
- How to ignore whitespace in a regular expression subject string?
- Regular expression for a string that does not start with a sequence
- Regex: matching up to the first occurrence of a character
- Regex credit card number tests
- Regular expression – starting and ending with a character string
- /bb|[^b]{2}/ how does it work?
- How do I match any character across multiple lines in a regular expression?
- Regular expression to remove HTML tags from a string
- Regex that matches integers in between whitespace or start/end of string only
- Regular Expressions- Match Anything
- My Vim replace with a regex is throwing a `E488: Trailing characters`
- Escaping Parentheses in Regex
- How to replace a string in an existing file in Perl
- Regex empty string or email
- Regex to validate date formats dd/mm/YYYY, dd-mm-YYYY, dd.mm.YYYY, dd mmm YYYY, dd-mmm-YYYY, dd/mmm/YYYY, dd.mmm.YYYY with Leap Year Support
- Regex difference: (\w+)? and (\w*)
- extract shortcodes from string
- preg_replace and comment_form_defaults
- 404 regular-expression advice needed
- How to use a variable as a className inside preg_match_all parameters?
- How to set up redirects for category paginated pages after adding /category/ to permalink
- Adding span tags to post titles using regex
- Remove Custom HTML Posts Using Regex
- Regexes allow only [a-z][A-Z][0-9] and –
- Call Shortcode Attribute Value within another function
- Regex For Extracting First 4 letters of search term
- Use Regex Redirection via htsaccess for RSS Feeds WordPress