Array#count

() -> ::Integer

(Elem obj) -> ::Integer

() { (Elem) -> ::boolish } -> ::Integer

count → integer

count(object) → integer

count {|element| ... } → integer

array.c View on GitHub ↗

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

    if (rb_check_arity(argc, 0, 1) == 0) {
        VALUE v;

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

        for (i = 0; i < RARRAY_LEN(ary); i++) {
            v = RARRAY_AREF(ary, i);
            if (RTEST(rb_yield(v))) n++;
        }
    }
    else {
        VALUE obj = argv[0];

        if (rb_block_given_p()) {
            rb_warn("given block not used");
        }
        for (i = 0; i < RARRAY_LEN(ary); i++) {
            if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
        }
    }

    return LONG2NUM(n);
}

Returns a count of specified elements.

With no argument and no block, returns the count of all elements:

Example

[0, :one, 'two', 3, 3.0].count # => 5

With argument object given, returns the count of elements == to object:

Example

[0, :one, 'two', 3, 3.0].count(3) # => 2

With no argument and a block given, calls the block with each element; returns the count of elements for which the block returns a truthy value:

Example

[0, 1, 2, 3].count {|element| element > 1 } # => 2

With argument object and a block given, issues a warning, ignores the block, and returns the count of elements == to object.

Related: see Methods for Querying.

See also #concat #cycle #compact! #delete also in 4.1 · 4.0 · 3.3 · 3.2 · 3.1 · 3.0

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