Str_replace() Not Every Occurence

Hello,

I've a string like "ab_cd_efg_h" and I want to change it into "ab_cd-efg-h"

I know the function

str_replace  ( '_'  , '-'  ,  'ab_cd_efg_h')

but it changes every occurrence of '_'

how can I specify to change one particular occurrence (just knowing its occurrence position, not the exact char number)

thank you

ok I've found a way of doing it

$str='ab_cd_efg_h'$end = str_replace('_', '-', $str);$end = preg_replace('/-/', '_', $end, 1);

if someone has a better way...

I think you should find out the pattern in the sequence.

Does "efg" appear every second "_"?

Does "efg" appear in 3, where other groups are 2 or less, i.e. aa_bb_efg_h or aaaa_b_efg_h?

Does "efg" appear as 3rd, whatever the string legth be, i.e. aa_bb_efg_hh_ii_jj or aaa_bbb_efg_hhh_iii_jjj_kkk?

You can even go before the string is formed, i.e. if "efg" is part of input from multiple places, isolate when "efg" is entered and assign a different variable

For example, aa_bb_$replace_h

And do

str_replace  ( '_$replace_'  , '-$replace-'  ,  'ab_cd_$replace_h')

how can I specify to change one particular occurrence (just knowing its occurrence position, not the exact char number)

Just use substr_replace() in combination with strpos() (unless you already know the exact position, then you can skip strpos()).

the string I gave was just an exempleI know that between the two first words (don't know the length), I should have _ and - between all the following (don't know how many and where)I can have ab_cd_efg_h as well than 123_4_56@truefusion : your solution seems good

Edited March 9, 2010 by martvefun (see edit history)