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instance method

Integer#[]

int[n] → 0, 1

int[n, m] → num

int[range] → num

static VALUE
int_aref(int const argc, VALUE * const argv, VALUE const num)
{
    rb_check_arity(argc, 1, 2);
    if (argc == 2) {
        return int_aref2(num, argv[0], argv[1]);
    }
    return int_aref1(num, argv[0]);

    return Qnil;
}

Bit Reference—Returns the nth bit in the binary representation of int, where int[0] is the least significant bit.

Example

a = 0b11001100101010
30.downto(0) {|n| print a[n] }
#=> 0000000000000000011001100101010

a = 9**15
50.downto(0) {|n| print a[n] }
#=> 000101110110100000111000011110010100111100010111001

In principle, n[i] is equivalent to (n >> i) & 1. Thus, any negative index always returns zero:

Example

p 255[-1] #=> 0

Range operations n[i, len] and n[i..j] are naturally extended.

n[i, len] equals to (n >> i) & ((1 << len) - 1).
n[i..j] equals to (n >> i) & ((1 << (j - i + 1)) - 1).
n[i...j] equals to (n >> i) & ((1 << (j - i)) - 1).
n[i..] equals to (n >> i).
n[..j] is zero if n & ((1 << (j + 1)) - 1) is zero. Otherwise, raises an ArgumentError.
n[...j] is zero if n & ((1 << j) - 1) is zero. Otherwise, raises an ArgumentError.

Note that range operation may exhaust memory. For example, -1[0, 1000000000000] will raise NoMemoryError.

See also #>> #^ #>= #| also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.1

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