Newbie Q: Difference between methods that use () and methods that allow a .

rubyonrails-talk
1

Hello,

Can anyone offer a pointer so that I can understand that difference between methods that use ( ) and methods that allow a .

If I want to use strip_tags, this will work for me:

    strip_tags("<b>cow</b>")

What I'm wondering is, why does this not work:

    "<b>cow</b>".strip_tags

but for a different method, say pluralize, this works:

    "cow".pluralize

For my particular usage, my code would be a lot cleaner if I could code like so:

    @comment.name.strip_tags     @comment.email.strip_tags     @comment.url.strip_tags     @comment.comment.strip_tags

instead, this is what I'm doing right now:

    @comment.name = strip_tags(@comment.name)     @comment.email = strip_tags(@comment.email)     @comment.url = strip_tags(@comment.url)     @comment.comment = strip_tags(@comment.comment)

Thanks,

Sean

2

If I want to use strip_tags, this will work for me:

    strip_tags("<b>cow</b>")

What I'm wondering is, why does this not work:

    "<b>cow</b>".strip_tags

Because the String object you create by doing "<b>cow</b>" doesn't have a strip_tags method.

but for a different method, say pluralize, this works:

    "cow".pluralize

Because String does have a pluralize method.

For my particular usage, my code would be a lot cleaner if I could code like so:

    @comment.name.strip_tags     @comment.email.strip_tags     @comment.url.strip_tags     @comment.comment.strip_tags

There's nothing stopping you from adding a strip_tags method to the String class:

class String    def strip_tags      .. do stuff ..    end end

Although based on the two examples you posted, you'd probably want to call the method strip_tags! and have it modify the current object instead of just returning the modified value like the strip_tags helper does.