Home/ Questions/Q 3393722
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-18T04:05:05+00:00

I’m trying to add tags to some given query strings, and the tags should

  • 0

I’m trying to add tags to some given query strings, and the tags should wrap around all the matching strings.
For example, I want to wrap tags around all the words that match the query iphone games mac in the sentence I love downloading iPhone games from my mac. It should be I love downloading <em>iPhone games</em> from my <em>mac</em>.

Currently, I tried

sentence = "I love downloading iPhone games from my mac."
query = r'((iphone|games|mac)\s*)+'
regex = re.compile(query, re.I)
sentence = regex.sub(r'<em>\1</em> ', sentence)

The sentence outputs

I love downloading <em>games </em> on my <em>mac</em> !

Where \1 is only replace by one word (games instead of iPhone games) and there are some unnecessary spaces after the word. How do I write the regular expression to get the desired output? Thanks!

Edit:
I just realized that both Fred and Chris’s solutions have problems when I have words within words. For instance, if my query is game, then it will turn out to be <em>game</em>s while I want it not be highlighted. Another example is the in either shouldn’t be highlighted.

Edit 2:
I took Chris’ new solution and it works.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    First of all, to get the spaces as you want them, replace \s* with \s*? to make it non-greedy.

    First fix:

    >>> re.compile(r'(((iphone|games|mac)\s*?)+)', re.I).sub(r'<em>\1</em>', sentence)
'I love downloading <em>iPhone</em> <em>games</em> from my <em>mac</em>.'

    Unfortunately, once the \s* is non-greedy, it splits phrases, as you can see. Without it, it goes like this, grouping the two together:

    >>> re.compile(r'(((iPhone|games|mac)\s*)+)').sub(r'<em>\1</em>', sentence)
'I love downloading <em>iPhone games </em>from my <em>mac</em>.'

    I can’t think yet how to fix this.

    Note also that in these I have stuck in an extra set of brackets around the + so that all matches get caught – that’s the difference.

    Further update: actually, I can think of a way to get around it. You decide whether you want it like that.

    >>> regex = re.compile(r'((iphone|games|mac)(\s*(iphone|games|mac))*)', re.I)
>>> regex.sub(r'<em>\1</em>', sentence)
'I love downloading <em>iPhone games</em> from my <em>mac</em>.'

    Update: taking your point about word boundaries into account, we only need to add in a few instances of \b, the word boundary matcher.

    >>> regex = re.compile(r'(\b(iphone|games|mac)\b(\s*(iphone|games|mac)\b)*)', re.I)
>>> regex.sub(r'<em>\1</em>', 'I love downloading iPhone games from my mac')
'I love downloading <em>iPhone games</em> from my <em>mac</em>'
>>> regex.sub(r'<em>\1</em>', 'I love downloading iPhone gameses from my mac')
'I love downloading <em>iPhone</em> gameses from my <em>mac</em>'
>>> regex.sub(r'<em>\1</em>', 'I love downloading iPhoney games from my mac')
'I love downloading iPhoney <em>games</em> from my <em>mac</em>'
>>> regex.sub(r'<em>\1</em>', 'I love downloading iPhoney gameses from my mac')
'I love downloading iPhoney gameses from my <em>mac</em>'
>>> regex.sub(r'<em>\1</em>', 'I love downloading miPhone gameses from my mac')
'I love downloading miPhone gameses from my <em>mac</em>'
>>> regex.sub(r'<em>\1</em>', 'I love downloading miPhone games from my mac')
'I love downloading miPhone <em>games</em> from my <em>mac</em>'
>>> regex.sub(r'<em>\1</em>', 'I love downloading iPhone igames from my mac')
'I love downloading <em>iPhone</em> igames from my <em>mac</em>'
    • 0