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Change strings in Rails?

So, I am new to Rails (teaching myself as a senior project in high school) and I am trying to figure out how to change these lines.

Let's say someone writes the following line in the form: "you know you are a geek when"

How can I automatically change it to this: "You know you're a geek when ..."?

I need Rails to check the case of the first letter and check for three dots, then change the string as needed. I've looked here , but I can't find anything that works.

Thank you very much!

EDIT: I'm trying to implement what Ruben Mallaby suggested, but I'm having problems. Here's the relevant part of the lists_controller.rb file, and below is the method in the list.rb model.

def update
  @list = List.find(params[:id])
  @list.fixlistname
  respond_to do |format|
    if @list.update_attributes(params[:list])
      flash[:notice] = 'List was successfully updated.'
      format.html { redirect_to(@list) }
      format.xml  { head :ok }
    else
      format.html { render :action => "edit" }
      format.xml  { render :xml => @list.errors, :status => :unprocessable_entity }
    end
  end
end

and..

def fixlistname
  new_title = title.humanize + (title.ends_with("...") ? "" : "...")
end

EDIT 2: I want the row to be modified before it enters the database, and this is the error message I am getting:

undefined method `ends_with 'for" You know you're a runner when ": String

GET THIS JOB! THANKS EVERYONE!

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4 answers


Can you use humanize to make sure the first letter is uppercase and end_with? ("...") to test three points



new_string = my_string.humanize + (my_string.ends_with?("...") ? "" : "...")
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Just a hint, but when you do "destructive" operations (operations that modify the caller), you must add an exclamation mark (!) To the end of the method name. This is just a convention, but it definitely increases readability and later reduces surprises.

So, in your controller, you will have:

@list.fixlistname!


and in your model you would:

def fixlistname!
  new_title = title.humanize + (title.ends_with?("...") ? "" : "...")
end

See here for details .

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String # capitalize will use the first letter of the string:

"you know you are a geek when".capitalize # => "You know you are a geek when"

And you can get the last three characters of a string using String # [] :

"you know"[-3,3]             # => "now"
"you know..."[-3,3]          # => "..."

"you know..."[-3,3] == "..." # => true

Rails also provides a nice shortcut for this in the form of String # ends_with? :

"you know...".ends_with?("...") # => true

So, you can check for the end of the line, and if it is not "...", you can add "...":

dots = "..."
my_str = "you know you are a geek when"

my_str = my_str + dots unless my_str.ends_with? dots
# => "you know you are a geek when..."

my_str.capitalize!
puts my_str
# => "You know you are a geek when..."

One edge case that you might want to consider is when the string ends with periods, but not three of them. For example, how would you handle a string like "you know .." (the above method would do it "you know .....") or "you know ....." (the above would leave that unchanged)?

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The way to check and modify strings with ruby ​​is to use regular expressions. You can read about them here and learn how to use them in Rubular

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