Simple programming q

ruby-talk
1

I am a ruby newbie. I want to make a simple script that replaces certain
characters in a block of text with specific other characters.

I am wondering what kind of loop or algo is thought to be most effective
for this kind of work..
Maybe go through the block of text with a hashing table and replace
each 'hit'? Would this be reasonable approach?

#example pseudocode idea
blokoftxt = 'Theres some text in block.'
replacekey = { 'T' = 'W', 'a' = 'o', 'o' = 'a' }

blokoftxt.each ( if equal to a replacekey, replace with key value )

This would mean going through each character in the textblock. I guess one
could conversely go through the replacekey array and match to the
textblock?? Which way to go?

J Von Rubiginner

2

I am a ruby newbie. I want to make a simple script that replaces certain
characters in a block of text with specific other characters.

I am wondering what kind of loop or algo is thought to be most effective
for this kind of work..
Maybe go through the block of text with a hashing table and replace
each 'hit'? Would this be reasonable approach?

#example pseudocode idea
blokoftxt = 'Theres some text in block.'
replacekey = { 'T' = 'W', 'a' = 'o', 'o' = 'a' }

blokoftxt.each ( if equal to a replacekey, replace with key value )

Here's a simple answer, using a regular expression.

blokoftxt = 'Theres some text in block.'
replacekey = { 'T' => 'W', 'a' => 'o', 'o' => 'b' }
replacekey.each {|key, val| blokoftxt.gsub!(/#{key}/, val)}

···

On 2/14/06, grrr <grrr@toto.maatti> wrote:

This would mean going through each character in the textblock. I guess one
could conversely go through the replacekey array and match to the
textblock?? Which way to go?

J Von Rubiginner

--
Bill Guindon (aka aGorilla)
The best answer to most questions is "it depends".

3

#example pseudocode idea
blokoftxt = 'Theres some text in block.'
replacekey = { 'T' = 'W', 'a' = 'o', 'o' = 'a' }

you can use String.gsub! to replace a pattern

replacekey.each_key {|key, value| blockoftext.gsub!(key, val) }

this works for your example, but not for something like {'.' => 't'}
because first parameter of gsub is a regexp!!

4

blokoftxt.tr 'Tao', 'Woa'

···

On Feb 14, 2006, at 3:33 PM, grrr wrote:

I am a ruby newbie. I want to make a simple script that replaces certain
characters in a block of text with specific other characters.

I am wondering what kind of loop or algo is thought to be most effective
for this kind of work..
Maybe go through the block of text with a hashing table and replace
each 'hit'? Would this be reasonable approach?

#example pseudocode idea
blokoftxt = 'Theres some text in block.'
replacekey = { 'T' = 'W', 'a' = 'o', 'o' = 'a' }

blokoftxt.each ( if equal to a replacekey, replace with key value )

--
Eric Hodel - drbrain@segment7.net - http://segment7.net
This implementation is HODEL-HASH-9600 compliant

http://trackmap.robotcoop.com

5

grrr wrote:

I am a ruby newbie. I want to make a simple script that replaces certain
characters in a block of text with specific other characters.

I am wondering what kind of loop or algo is thought to be most effective
for this kind of work.. Maybe go through the block of text with a hashing table and replace
each 'hit'? Would this be reasonable approach?

#example pseudocode idea
blokoftxt = 'Theres some text in block.'
replacekey = { 'T' = 'W', 'a' = 'o', 'o' = 'a' }

blokoftxt.each ( if equal to a replacekey, replace with key value )

This would mean going through each character in the textblock. I guess one
could conversely go through the replacekey array and match to the
textblock?? Which way to go?

J Von Rubiginner

text = <<-ENDTEXT
The Owl and the Pussy-cat went to sea
     In a beautiful pea green boat,
They took some honey, and plenty of money,
     Wrapped up in a five pound note.
The Owl looked up to the stars above,
     And sang to a small guitar,
'O lovely Pussy! O Pussy my love,
       What a beautiful Pussy you are,
           You are,
           You are!
What a beautiful Pussy you are!'
ENDTEXT

replace_key = { 'O' => 'd', 'P' => 'w', 'b' => 'x'}
new_text = text.gsub(/[#{replace_key.keys.join}]/) {|match|
  replace_key[match]
}
puts new_text

The result is:

The dwl and the wussy-cat went to sea
     In a xeautiful pea green xoat,
They took some honey, and plenty of money,
     Wrapped up in a five pound note.
The dwl looked up to the stars axove,
     And sang to a small guitar,
'd lovely wussy! d wussy my love,
       What a xeautiful wussy you are,
           You are,
           You are!
What a xeautiful wussy you are!'

6

Haha! That's awesome. (sorry, I'm easily amused)

-Harold

···

>
> #example pseudocode idea
> blokoftxt = 'Theres some text in block.'
> replacekey = { 'T' = 'W', 'a' = 'o', 'o' = 'a' }
>
> blokoftxt.each ( if equal to a replacekey, replace with key value )

blokoftxt.tr 'Tao', 'Woa'

--
Eric Hodel

7

Re:

Eric Hodel:
blokoftxt.tr 'Tao', 'Woa'

Haha! That's awesome. (sorry, I'm easily amused)

-Harold

Yes indeed! Hehe I guess I am easily amused, too!

Thats pretty much the solution I was looking for, even if I was expecting
replies from Knuths books. Thanks Eric!

···

On Wed, 15 Feb 2006 10:12:41 +0900, Harold Hausman wrote: