Asp Forum - Re: What is that method called?

Mike Paul

11/11/2008 10:10:00 AM

Hi David - just done this in Agile Development

truncate(string, n) where string is the string to be shortened and n is the
number of characters you want it shortened to.

Cheers
Mike

-----Original Message-----
From: davidtrasbo@gmail.com [mailto:davidtrasbo@gmail.com]
Sent: 11 November 2008 09:17
To: ruby-talk ML
Subject: What is that method called?

I need the method that has the ability to turn a long string like this:

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque
pulvinar turpis a nisi. Cras id elit. Aliquam vitae pede nec lacus
elementum lacinia. Ut aliquam vehicula sem.

into a shorter string like this:

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque
pulvinar turpis...

My problem is that I can't remember what the method is called. I looked
through the whole Ruby String documentation
(http://ruby-doc.org/core/classes/S...) but I couldn't find it.
Can anyone remember what it's called?
--
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7 Answers

David Trasbo

11/11/2008 10:47:00 AM

Peter Szinek wrote:
> I seriously doubt this is part of standard Ruby.

You're right, it's not a part of the Ruby standard library:

Clifford Heath wrote:
> There's no such method in Ruby. You might be thinking of the
> truncate method that's part of ActionView's TextHelper module.

truncate is what it's called. I was actually searching for 'rails
StringHelper'... :)

Thanks for the replies!
--
Posted via http://www.ruby-....

Justin Collins

11/11/2008 11:12:00 AM

[Note: parts of this message were removed to make it a legal post.]

David Trasbo wrote:
> Peter Szinek wrote:
>
>> I seriously doubt this is part of standard Ruby.
>>
>
> You're right, it's not a part of the Ruby standard library:
>
> Clifford Heath wrote:
>
>> There's no such method in Ruby. You might be thinking of the
>> truncate method that's part of ActionView's TextHelper module.
>>
>
> truncate is what it's called. I was actually searching for 'rails
> StringHelper'... :)
>
> Thanks for the replies!
>

Also:

a_long_string = "Lorem ipsum dolor sit amet, consectetuer adipiscing
elit. Pellentesque pulvinar turpis a nisi. Cras id elit. Aliquam vitae
pede nec lacus elementum lacinia. Ut aliquam ehicula sem."
limit = 86
a_long_string[0, limit] << "..." #=> "Lorem ipsum dolor sit amet,
consectetuer adipiscing elit. Pellentesque pulvinar turpis..."

-Justin

Boris Blaadh

11/11/2008 2:30:00 PM

perhaps this works?

string = <<END
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque
pulvinar turpis a nisi. Cras id elit. Aliquam vitae pede nec lacus
elementum lacinia. Ut aliquam vehicula sem.
END

lead = 90

wordlist = string.split(' ')

shorttext = ''

for word in wordlist

break if(shorttext.length + word.length > lead)
shorttext = shorttext + word + " "

end

# get rid of the last space
shorttext.chop!

puts "#{shorttext}..."
--
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Brian Adkins

11/11/2008 5:52:00 PM

Justin Collins <justincollins@ucla.edu> writes:

> [Note: parts of this message were removed to make it a legal post.]
>
> David Trasbo wrote:
>> Peter Szinek wrote:
>>
>>> I seriously doubt this is part of standard Ruby.
>>>
>>
>> You're right, it's not a part of the Ruby standard library:
>>
>> Clifford Heath wrote:
>>
>>> There's no such method in Ruby. You might be thinking of the
>>> truncate method that's part of ActionView's TextHelper module.
>>>
>>
>> truncate is what it's called. I was actually searching for 'rails
>> StringHelper'... :)
>>
>> Thanks for the replies!
>>
>
> Also:
>
> a_long_string = "Lorem ipsum dolor sit amet, consectetuer adipiscing
> elit. Pellentesque pulvinar turpis a nisi. Cras id elit. Aliquam vitae
> pede nec lacus elementum lacinia. Ut aliquam ehicula sem."
> limit = 86
> a_long_string[0, limit] << "..." #=> "Lorem ipsum dolor sit amet,
> consectetuer adipiscing elit. Pellentesque pulvinar turpis..."

In general, for input strings less than the limit, you wouldn't want "..."

class String
# Return an ellided string no longer than total_length
# "hello".ellide(5) -> "hello"
# "hello there".ellide(8) -> "hello..."
def ellide total_length
if self.length > total_length
raise 'total_length must be at least 3' if total_length < 3
return self[0, total_length - 3] + '...'
else
return self
end
end
end

>
> -Justin
>

--
Brian Adkins
http://www....
http://lojic...

Brian Adkins

11/11/2008 5:57:00 PM

Boris Blaadh <nejnejnej@gmail.com> writes:

> perhaps this works?
>
> string = <<END
> Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque
> pulvinar turpis a nisi. Cras id elit. Aliquam vitae pede nec lacus
> elementum lacinia. Ut aliquam vehicula sem.
> END
>
> lead = 90
>
> wordlist = string.split(' ')
>
> shorttext = ''
>
> for word in wordlist
>
> break if(shorttext.length + word.length > lead)
> shorttext = shorttext + word + " "
>
> end
>
> # get rid of the last space
> shorttext.chop!
>
> puts "#{shorttext}..."

It is nicer to break at word boundaries in some contexts. But if it's
a single word (such as a long email address), then you'd still want to
show something more than "...". Maybe you can add a check for that.

e.g. for string = 'john.smith@hisdomain.com', lead = 15

--
Brian Adkins
http://www....
http://lojic...

Boris Blaadh

11/12/2008 11:39:00 AM

Brian Adkins wrote:
> Boris Blaadh <nejnejnej@gmail.com> writes:
>
>> wordlist = string.split(' ')
>> # get rid of the last space
>> shorttext.chop!
>>
>> puts "#{shorttext}..."
>
> It is nicer to break at word boundaries in some contexts. But if it's
> a single word (such as a long email address), then you'd still want to
> show something more than "...". Maybe you can add a check for that.
>
> e.g. for string = 'john.smith@hisdomain.com', lead = 15

Hehe, ok:

if shorttext.empty?
puts wordlist[0]
else
puts "#{shorttext}..."
end
--
Posted via http://www.ruby-....

Brian Adkins

11/12/2008 8:55:00 PM

Boris Blaadh <nejnejnej@gmail.com> writes:

> Brian Adkins wrote:
>> Boris Blaadh <nejnejnej@gmail.com> writes:
>>
>>> wordlist = string.split(' ')
>>> # get rid of the last space
>>> shorttext.chop!
>>>
>>> puts "#{shorttext}..."
>>
>> It is nicer to break at word boundaries in some contexts. But if it's
>> a single word (such as a long email address), then you'd still want to
>> show something more than "...". Maybe you can add a check for that.
>>
>> e.g. for string = 'john.smith@hisdomain.com', lead = 15
>
> Hehe, ok:
>
> if shorttext.empty?
> puts wordlist[0]
> else
> puts "#{shorttext}..."
> end

That fixes the problem of showing only '...', but now 'puts
wordlist[0]' may display more than the limit.

Refining your idea a bit gave the following:

def elide_words total_length
return self unless self.length > total_length
raise 'total_length must be at least 3' if total_length < 3
words = self.split(' ')
result = ''
words.each do |word|
len = total_length - (result.empty? ? 3 : 4)
break if result.length + word.length > len
result << ' ' unless result.empty?
result << word
end
if result.empty?
return self.elide(total_length)
else
return result + '...'
end
end

But we really don't need to find *all* the space boundaries via
split(), so the following version is about 10 times faster:

def elide_words total_length
return self unless self.length > total_length
raise 'total_length must be at least 3' if total_length < 3
len = total_length - 3 # room for '...'

# Case 1: natural word break
return self[0, len] + '...' if self[len,1] == ' '

# Case 2: search backward for a char preceding a delimiter
delim_found = false
idx = len.downto(0) {|i|
if delim_found
break (i + 1) if self[i,1] != ' '
else
delim_found = true if self[i,1] == ' '
end
}

return self[0, idx] + '...'
end

--
Brian Adkins
http://www....
http://lojic...

comp.lang.ruby

Re: What is that method called?

Mike Paul

David Trasbo

Justin Collins

Boris Blaadh

Brian Adkins

Brian Adkins

Boris Blaadh

Brian Adkins

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