End of Life Ruby 3.0 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →
instance method
Enumerable#find_index
enum.find_index(value) → int or nil
enum.find_index { |obj| block } → int or nil
enum.find_index → an_enumerator
enum.c
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static VALUE
enum_find_index(int argc, VALUE *argv, VALUE obj)
{
struct MEMO *memo; /* [return value, current index, ] */
VALUE condition_value = Qnil;
rb_block_call_func *func;
if (argc == 0) {
RETURN_ENUMERATOR(obj, 0, 0);
func = find_index_iter_i;
}
else {
rb_scan_args(argc, argv, "1", &condition_value);
if (rb_block_given_p()) {
rb_warn("given block not used");
}
func = find_index_i;
}
memo = MEMO_NEW(Qnil, condition_value, 0);
rb_block_call(obj, id_each, 0, 0, func, (VALUE)memo);
return memo->v1;
}
Compares each entry in enum with value or passes to block. Returns the index for the first for which the evaluated value is non-false. If no object matches, returns nil
If neither block nor argument is given, an enumerator is returned instead.
Example
(1..10).find_index { |i| i % 5 == 0 && i % 7 == 0 } #=> nil (1..100).find_index { |i| i % 5 == 0 && i % 7 == 0 } #=> 34 (1..100).find_index(50) #=> 49