method

count

v1_9_2_180 - Show latest stable - Class: Array

count(p1)

public

Returns the number of elements. If an argument is given, counts the number of elements which equals to obj. If a block is given, counts the number of elements yielding a true value.

ary = [1, 2, 4, 2]
ary.count             #=> 4
ary.count(2)          #=> 2
ary.count{|x|x%2==0}  #=> 3

static VALUE
rb_ary_count(int argc, VALUE *argv, VALUE ary)
{
    long n = 0;

    if (argc == 0) {
        VALUE *p, *pend;

        if (!rb_block_given_p())
            return LONG2NUM(RARRAY_LEN(ary));

        for (p = RARRAY_PTR(ary), pend = p + RARRAY_LEN(ary); p < pend; p++) {
            if (RTEST(rb_yield(*p))) n++;
        }
    }
    else {
        VALUE obj, *p, *pend;

        rb_scan_args(argc, argv, "1", &obj);
        if (rb_block_given_p()) {
            rb_warn("given block not used");
        }
        for (p = RARRAY_PTR(ary), pend = p + RARRAY_LEN(ary); p < pend; p++) {
            if (rb_equal(*p, obj)) n++;
        }
    }

    return LONG2NUM(n);
}

count

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