Simple programming q


#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

On 2/14/06, grrr removed_email_address@domain.invalid wrote:

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)}


#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

grrr wrote:

replacekey = { ‘T’ = ‘W’, ‘a’ = ‘o’, ‘o’ = ‘a’ }

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!’


#5

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

#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 H. - removed_email_address@domain.invalid - http://segment7.net
This implementation is HODEL-HASH-9600 compliant

http://trackmap.robotcoop.com


#6

Re:

Eric H.:
blokoftxt.tr ‘Tao’, ‘Woa’

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

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!


#7

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

-Harold