Skip to content



replace_string() - replace all instances of a string within a string


string replace_string( str, pattern, replace );
string replace_string( str, pattern, replace, max );
string replace_string( str, pattern, replace, first, last );

string str, pattern replace;
int max, first, last;


replace_string()  returns  str  with  all instances of pattern replaced
with replace.  If pattern has zero length then str is returned  unmodi‐
fied.   If  the resultant string would exceed the maximum string length
then replace_string() returns an undefinedp(), non-stringp() value.

replace_string() can be used to remove  characters  from  a  string  by
specifying a pattern and a zero-length replace parameter.  For example,
replace_string("  1  2  3   ",   "   ",   "")   would   return   "123".
replace_string() executes faster this way then explode()/implode().

The  4th and 5th arguments are optional (to retain backward compatibil‐
ity.)  The extra arguments have the following effect:

4 args
    The 4th argument specifies the maximum number  of  replacements  to
    make  (the  count starts at 1). A value of 0 implies 'replace all',
    and thus, acts as replace_string() with 3  arguments  would.  E.g.,
    replace_string("xyxx", "x", "z", 2) would return "zyzx".

5 args
    The  4th  and 5th arguments specify the range of matches to replace
    between, with the following constraints:
    - first < 1 : change all from the start.
    - last == 0, or last > max_matches : change all to end
    - first > last : return the unmodified array.
    E.g., replace_string("xyxxy", "x", "z", 2, 3) returns "xyzzy".


sscanf(3), explode(3), strsrch(3)


Zak@TMI-2 wrote the range constraint additions.