Regex for multiple words separated by spaces or commas

Question

I'm trying to create regex for multiple strings separated by comma or space.

Lorem Ipsum // valid
Lorem, Ipsum //valid
Lorem, Ipsum, Ipsum, Ipsum // multiple valid
Lorem // invalid without space/comma

Here is what i have so far:

^\w+(,\s*\w+){3}$/

Answer 1

You may use

^\w+(?:(?:,\s\w+)+|(?:\s\w+)+)$

See the regex demo.

The regex matches:

• ^ - start of string
• \w+ - 1+ word chars
• (?: - start of an alternation group:
  • (?:,\s\w+)+ - ,, whitespace, 1+ word chars
  • | - or
  • (?:\s\w+)+ - whitespace and then 1+ word chars
• ) - end of group
• $ - end of string.

You may shorten the pattern using a lookahead and a capturing group:

^\w+(?=(,?\s))(?:\1\w+)+$

See the regex demo. Here, the difference is (?=(,?\s))(?:\1\w+)+:

• (?=(,?\s)) - a positive lookahead that checks if there is an optional , and then a whitespace immediately to the right of the current location and captures that sequence into Group 1
• (?:\1\w+)+ - 1 or more sequences of:
  • \1 - the same text captured into Group 1
  • \w+ - 1+ word chars.

See the regex demo.

Answer 2

Try this regex:

^(\w+[, ]+)*\w+$