Search code examples
phpregexpreg-replacelimithashtag

Add newlines to separate text and only hashtags that appear at the end of the string

I've already tried a couple of regex but cannot fix this one:

I need an enter line before the hashtags start (so there is some space).

Example:

It's essential to keep your pup cool in the summer months! Try to keep them out of the heat as much as possible - keep the house cool, provide shade and run a fan for them if you can. #Dogs #Animals #Summer #DogCare #Humidity #HeatStroke #Cooling #HeatExhaustion #StayCool #HealthyPups

Should be:

It's essential to keep your pup cool in the summer months! Try to keep them out of the heat as much as possible - keep the house cool, provide shade and run a fan for them if you can.

#Dogs #Animals #Summer #DogCare #Humidity #HeatStroke #Cooling #HeatExhaustion #StayCool #HealthyPups

If there is a hashtag in the text it should not add whitespace, for example (note hashtags in text!):

It's essential to keep your pup cool in the summer months! Try to keep them out of the heat as much as #possible - keep the house cool, #provide shade and run a #fan for them if #you can. #Dogs #Animals #Summer #DogCare #Humidity #HeatStroke #Cooling #HeatExhaustion #StayCool #HealthyPups

How can I solve this with Regex and PHP?

Solution

  • You can match a series of hashtags with the regexp:

    (?:#\w+\s*)+$
    • #\w+ matches a single hashtag
    • \s* matches the optional whitespace between the hashtags
    • + after the group matches a sequence of at least one of these
    • $ matches the end of the input string.

    You can then use preg_replace() to insert a blank line before this.

    $text = preg_replace('/((?:#\w+\s*)+)$/', "\n\n$1", $text);