instance method
String#slice!
(::int index, ?::int length) -> ::String?
(::range[::int?] range) -> ::String?
(::String substring) -> ::String?
(::Regexp regexp, ?::MatchData::capture backref) -> ::String?
slice!(index) → new_string or nil
slice!(start, length) → new_string or nil
slice!(range) → new_string or nil
slice!(regexp, capture = 0) → new_string or nil
slice!(substring) → new_string or nil
string.c
View on GitHub ↗
static VALUE
rb_str_slice_bang(int argc, VALUE *argv, VALUE str)
{
VALUE result = Qnil;
VALUE indx;
long beg, len = 1;
char *p;
rb_check_arity(argc, 1, 2);
str_modify_keep_cr(str);
indx = argv[0];
if (RB_TYPE_P(indx, T_REGEXP)) {
if (rb_reg_search(indx, str, 0, 0) < 0) return Qnil;
VALUE match = rb_backref_get();
struct re_registers *regs = RMATCH_REGS(match);
int nth = 0;
if (argc > 1 && (nth = rb_reg_backref_number(match, argv[1])) < 0) {
if ((nth += regs->num_regs) <= 0) return Qnil;
}
else if (nth >= regs->num_regs) return Qnil;
beg = BEG(nth);
len = END(nth) - beg;
goto subseq;
}
else if (argc == 2) {
beg = NUM2LONG(indx);
len = NUM2LONG(argv[1]);
goto num_index;
}
else if (FIXNUM_P(indx)) {
beg = FIX2LONG(indx);
if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
if (!len) return Qnil;
beg = p - RSTRING_PTR(str);
goto subseq;
}
else if (RB_TYPE_P(indx, T_STRING)) {
beg = rb_str_index(str, indx, 0);
if (beg == -1) return Qnil;
len = RSTRING_LEN(indx);
result = str_duplicate(rb_cString, indx);
goto squash;
}
else {
switch (rb_range_beg_len(indx, &beg, &len, str_strlen(str, NULL), 0)) {
case Qnil:
return Qnil;
case Qfalse:
beg = NUM2LONG(indx);
if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
if (!len) return Qnil;
beg = p - RSTRING_PTR(str);
goto subseq;
default:
goto num_index;
}
}
num_index:
if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
beg = p - RSTRING_PTR(str);
subseq:
result = rb_str_new(RSTRING_PTR(str)+beg, len);
rb_enc_cr_str_copy_for_substr(result, str);
squash:
if (len > 0) {
if (beg == 0) {
rb_str_drop_bytes(str, len);
}
else {
char *sptr = RSTRING_PTR(str);
long slen = RSTRING_LEN(str);
if (beg + len > slen) /* pathological check */
len = slen - beg;
memmove(sptr + beg,
sptr + beg + len,
slen - (beg + len));
slen -= len;
STR_SET_LEN(str, slen);
TERM_FILL(&sptr[slen], TERM_LEN(str));
}
}
return result;
}
Like String#[] (and its alias String#slice), except that:
-
Performs substitutions in
self(not in a copy ofself). -
Returns the removed substring if any modifications were made,
nilotherwise.
A few examples:
Example
s = 'hello' s.slice!('e') # => "e" s # => "hllo" s.slice!('e') # => nil s # => "hllo"
Related: see Modifying.
Ruby version changes
-
3.0
-
The following methods now return or yield
Stringinstances instead of subclass instances when called on subclass instances: [Bug #10845]
-