How to group the following strings by regular expression

Question

This is the string I want to process.(At least one of the underlined parts. The last part is never underlined )

'_A._B._C._D._F.f'`

I expected

["A", "B", "C", "D", "F", "f"]

How to achieve the same effect by regularity, I tried, but can't loop the same format part.

new RegExp('^[(_(.+)\\.)]+(.+)$')

Answer 1

You could exclude dot and underscore from matching.

 var string = '_A._B._C._D._F.f', result = string.match(/[^._]+/g); console.log(result); 

Answer 2

How about that without using regex?

 str = '_A._B._C._D._F.f'.split('.') var alphabets = str.map(c => c.replace('_', '')); console.log(alphabets); 

Answer 3

You can use split that removes [._]+ (any substring containing dots or floors) and the filter (to remove the initial empty string):

'_A._B._C._D._F.f'.split(/[._]+/).filter(function(s){ return s.length > 0})
# => [ "A", "B", "C", "D", "F", "f" ]

EDIT: Simplification suggested in comments:

'_A._B._C._D._F.f'.split(/[._]+/).filter(Boolean)
# =>  [ "A", "B", "C", "D", "F", "f" ]

Answer 4

In your regex you try to match the whole pattern using an anchor ^ to assert the start of the string followed by a character class which will match only one out of several characters (and might for example also be written as [_(+\\\\.)]+ ) and then you capture the rest of the string in a capturing group and assert the end of the line $ .

If you want to check the format of the string first, you might use a more exact pattern. When that pattern matches, you could do a case insensitive match for a single character as the pattern is already validated:

 const regex = /^_[AZ](?:\\._[AZ])+\\.[az]$/; const str = `_A._B._C._D._F.f`; if (regex.test(str)) { console.log(str.match(/[az]/ig)); } 

See the regex demo

That will match:

• ^ Assert the start of the strin
• _[AZ] Match an underscore and an uppercase character
• (?:\\._[AZ])+ 1+ times repeated grouping structure to match ._ followed by an uppercase character
• \\.[az] Match a dot and a lowercase character
• $ Assert the end of the line

Answer 5

字符串方法.match与全局标志，可以帮助您：

 console.log('_A._B._C._D._F.f'.match(/[az]+/gi))