Here is a regular expression I created to use in JavaScript:
var reg_num = /^(7|8|9)\d{9}$/
Here is another one suggested by my team member.
var reg_num = /^[7|8|9][\d]{9}$/
The rule is to validate a phone number:
- It should be of only ten numbers.
- The first number is supposed to be any of 7, 8 or 9.
ベストアンサー1
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.