Better way to build string

ruby-talk
1

I'm trying to build a query string based on an array of properties. Is there a shorter/nicer way to do the following?

   def build_query_string(properties, prop_type)
     result = ""

     properties.each do |item|
       if prop_type == "tag"
         result += " #{item.name}=#{item.value}"
       else
         if result == ""
           result = "?"
         else
           result += "&"
         end
         result += "#{item.name}=#{item.value}"
       end
     end

     result
   end

/Marcus

2

I always find it useful to post code that is runnable
by copy+paste so people trying to help me don't have
to implement all the helper stuff first.

···

--- Ursprüngliche Nachricht ---
Von: marcus <m-lists@bristav.se>
An: ruby-talk@ruby-lang.org (ruby-talk ML)
Betreff: Better way to build string
Datum: Wed, 9 Nov 2005 03:41:28 +0900

I'm trying to build a query string based on an array of properties. Is
there a shorter/nicer way to do the following?

   def build_query_string(properties, prop_type)
     result = ""

     properties.each do |item|
       if prop_type == "tag"
         result += " #{item.name}=#{item.value}"
       else
         if result == ""
           result = "?"
         else
           result += "&"
         end
         result += "#{item.name}=#{item.value}"
       end
     end

     result
   end

/Marcus

3

def build_query_string(properties, prop_type)
  query = properties.map {|p| "#{p.name}=#{p.value}"}
  case prop_type
    when "tag": (" " + query.join(" "))
    else ("?" + query.join("&"))
  end
end

···

--- Ursprüngliche Nachricht ---
Von: marcus <m-lists@bristav.se>
An: ruby-talk@ruby-lang.org (ruby-talk ML)
Betreff: Better way to build string
Datum: Wed, 9 Nov 2005 03:41:28 +0900

I'm trying to build a query string based on an array of properties. Is
there a shorter/nicer way to do the following?

   def build_query_string(properties, prop_type)
     result = ""

     properties.each do |item|
       if prop_type == "tag"
         result += " #{item.name}=#{item.value}"
       else
         if result == ""
           result = "?"
         else
           result += "&"
         end
         result += "#{item.name}=#{item.value}"
       end
     end

     result
   end

/Marcus

4

marcus wrote:

I'm trying to build a query string based on an array of properties. Is there a shorter/nicer way to do the following?

  def build_query_string(properties, prop_type)
    result = ""

    properties.each do |item|
      if prop_type == "tag"
        result += " #{item.name}=#{item.value}"
      else
        if result == ""
          result = "?"
        else
          result += "&"
        end
        result += "#{item.name}=#{item.value}"
      end
    end

    result
  end

Perhaps you can modify this for your needs:

properties.inject('?') {|memo, (key, value)| memo << "#{key}=#{value}&" }

/Marcus

E

5

Eero Saynatkari <ruby-ml@magical-cat.org> writes:

Perhaps you can modify this for your needs:

properties.inject('?') {|memo, (key, value)| memo << "#{key}=#{value}&" }

FWIW, I've had a mental block about inject for some time, and this
example very nicely clarified for me what it does and how. Thanks for
the handy example.

Note to OP: Don't forget to use CGI::escape() to properly URL-encode
everything.

-=Eric

6

"?" + properties.map { |pair| pair.join('=') }.join('&')

Shorter, more expressive, omits the trailing '&'

···

On Nov 8, 2005, at 11:00 AM, Eero Saynatkari wrote:

marcus wrote:

I'm trying to build a query string based on an array of properties. Is there a shorter/nicer way to do the following?
  def build_query_string(properties, prop_type)
    result = ""
    properties.each do |item|
      if prop_type == "tag"
        result += " #{item.name}=#{item.value}"
      else
        if result == ""
          result = "?"
        else
          result += "&"
        end
        result += "#{item.name}=#{item.value}"
      end
    end
    result
  end

Perhaps you can modify this for your needs:

properties.inject('?') {|memo, (key, value)| memo << "#{key}=#{value}&" }

--
Eric Hodel - drbrain@segment7.net - http://segment7.net
FEC2 57F1 D465 EB15 5D6E 7C11 332A 551C 796C 9F04

7

Thank you everyone. I went with this one as it was the only one who took everything into account

Peter Ertl wrote:

def build_query_string(properties, prop_type)
  query = properties.map {|p| "#{p.name}=#{p.value}"}
  case prop_type
    when "tag": (" " + query.join(" "))
    else ("?" + query.join("&"))
  end
end

/Marcus