OpenEuphoria

1. match_replace for every instance forever

• Posted by euphoric (admin) Nov 08, 2011
• 1292 views

I want to turn all multiple space sequences in a string to a single space. For example:

x = match_replace( "  ","a  b    c d   e   f  g    h"," ") 
-- so x should be "a b c d e f g h" 

I thought we had a match_count() function, but can't find anything like that in the manual. I figured I could loop

while match_count("  ",x) > 0 do 
   x = match_replace( "  ",x," ") 
end while 

Or maybe match_replace() can be made to be recursive, but I don't see a flag for that. (In fact, the docs state "Replacements will not be made recursively on the part of haystack that was already changed." Maybe we could change that?)

Or... anybody know how to do this most quickly and efficiently?

3. Re: match_replace for every instance forever

• Posted by mattlewis (admin) Nov 08, 2011
• 1297 views

I'd do it with a slightly modified version of the std routine match_replace:

public function match_replace_all(object needle, sequence haystack, object replacement ) 
	integer posn 
	integer needle_len 
	integer replacement_len 
	integer scan_from 
	integer cnt 
	 
	if max < 0 then 
		return haystack 
	end if 
	 
	cnt = length(haystack) 
	if max != 0 then 
		cnt = max 
	end if 
	 
	if atom(needle) then 
		needle = {needle} 
	end if 
	if atom(replacement) then 
		replacement = {replacement} 
	end if 
 
	needle_len = length(needle) - 1 
	replacement_len = length(replacement) 
 
	scan_from = 1 
	while posn with entry do 
		haystack = replace(haystack, replacement, posn, posn + needle_len) 
 
		cnt -= 1 
		if cnt = 0 then 
			exit 
		end if 
		scan_from = posn + 1 -- <--- this is the change. Used to be "+ replacement_len" 
	entry 
		posn = match(needle, haystack, scan_from) 
	end while 
 
	return haystack 
end function 

Matt

5. Re: match_replace for every instance forever

• Posted by euphoric (admin) Nov 08, 2011
• 1290 views

-- ck.ex 
include std/regex.e 
include std/console.e 
regex r = regex:new( " +" ) 
display( regex:find_replace( r, "a  b    c d   e   f  g    h"," ") ) 

$ eui ck.ex 
a b c d e f g h 

Thanks, Matt! I really gotta learn regex...