Integer
An integer can be positiv or negative and is always internally represented by a 64-Bit Integer.
To cast a negative integer a digit can be prefixed with a - eg. -456.
a = 1;
b = a + 2;
is_true = 1 == 1;
is_false = 1 == 2;
Literal Specific Methods​
abs()​
Returns
INTEGER
Returns the absolute value, as an integer, keeping the base.
3.abs()
(0 - 5).abs()
"-0x10".to_i().abs()
3
5
0x10
base()​
Returns
INTEGER
Returns the base of the integer.
"0b1010".to_i().base()
2
bit_length()​
Returns
INTEGER
Returns how many bits are needed to represent the number, not counting the sign. A negative number needs as many as its complement, so -256 is 8 bits just like 255.
255.bit_length()
256.bit_length()
0.bit_length()
8
9
0
ceil([INTEGER])​
Returns
INTEGER
Rounds up to a multiple of ten, given a negative digit count. An integer is already exact, so no argument, or a count of zero or more, returns it unchanged.
555.ceil(0 - 1)
555.ceil(0 - 2)
555.ceil()
560
600
555
chr()​
Returns
STRING|ERROR
Returns the character with this code point, as a string. The inverse of a single entry of string.ascii(). A value outside the range of a character is an error.
65.chr()
"A"
digits([INTEGER])​
Returns
ARRAY|ERROR
Returns the digits of the number, least significant first, in base 10 or in a given base. A negative number has no digits and gives an error.
12345.digits()
12345.digits(7)
0.digits()
[5, 4, 3, 2, 1]
[4, 6, 6, 0, 5]
[0]
divmod(INTEGER)​
Returns
ARRAY|ERROR
Returns the quotient and the remainder as a two-element array. Both follow the / and % operators, which truncate toward zero. Ruby floors instead, so it answers [-3, -1] for the second example below.
11.divmod(4)
11.divmod(0 - 4)
[2, 3]
[-2, 3]
downto(INTEGER, CALLABLE)​
Returns
INTEGER|ERROR
Calls the callback with each integer from the receiver down to the given limit, inclusive at both ends, and returns the receiver. A limit above the receiver calls nothing.
3.downto(1, def(i) puts(i) end)
3
2
1
3
even?()​
Returns
BOOLEAN
Returns true when the number divides by two exactly.
4.even?()
5.even?()
true
false
floor([INTEGER])​
Returns
INTEGER
Rounds down to a multiple of ten, given a negative digit count. No argument, or a count of zero or more, returns the number unchanged.
555.floor(0 - 1)
555.floor(0 - 2)
550
500
gcd(INTEGER)​
Returns
INTEGER|ERROR
Returns the greatest common divisor of the two numbers, always positive. Like the infix operators, it refuses two integers of different bases.
36.gcd(60)
3.gcd(0 - 7)
12
1
lcm(INTEGER)​
Returns
INTEGER|ERROR
Returns the least common multiple of the two numbers, always positive.
36.lcm(60)
3.lcm(0 - 7)
180
21
negative?()​
Returns
BOOLEAN
Returns true when the number is less than zero.
(0 - 1).negative?()
0.negative?()
true
false
odd?()​
Returns
BOOLEAN
Returns true when the number does not divide by two exactly.
5.odd?()
4.odd?()
true
false
positive?()​
Returns
BOOLEAN
Returns true when the number is greater than zero.
1.positive?()
0.positive?()
true
false
pow(INTEGER, [INTEGER])​
Returns
INTEGER|ERROR
Returns the number raised to the given power. A second argument takes the result modulo it, which keeps large exponents workable. A negative exponent is an error, since the result would not be an integer.
2.pow(3)
2.pow(3, 5)
8
3
pred()​
Returns
INTEGER
Returns the previous integer, keeping the base of the receiver.
1.pred()
0.pred()
0
-1
round([INTEGER])​
Returns
INTEGER
Rounds to the nearest multiple of ten, halves away from zero, given a negative digit count. No argument, or a count of zero or more, returns the number unchanged.
555.round(0 - 1)
554.round(0 - 1)
560
550
succ()​
Returns
INTEGER
Returns the next integer, keeping the base of the receiver.
1.succ()
2
times(CALLABLE)​
Returns
INTEGER|ERROR
Calls the callback with each integer from 0 up to one less than the receiver, and returns the receiver so calls can be chained. A count of zero or less calls nothing rather than erroring, which makes it safe to hand a computed count. The counter keeps the receiver's base.
3.times(def(i) puts(i) end)
0.times(def(i) puts("never") end)
0
1
2
3
0
to_base(INTEGER)​
Returns
INTEGER
Converts the integer into a integer with the given base
"0b1010".to_i().to_base(8)
0o12
truncate([INTEGER])​
Returns
INTEGER
Drops the last digits, rounding toward zero, given a negative digit count. No argument, or a count of zero or more, returns the number unchanged.
555.truncate(0 - 1)
(0 - 555).truncate(0 - 1)
550
-550
upto(INTEGER, CALLABLE)​
Returns
INTEGER|ERROR
Calls the callback with each integer from the receiver up to the given limit, inclusive at both ends, and returns the receiver. A limit below the receiver calls nothing.
1.upto(3, def(i) puts(i) end)
3.upto(1, def(i) puts("never") end)
1
2
3
1
3
zero?()​
Returns
BOOLEAN
Returns true when the number is zero.
0.zero?()
1.zero?()
true
false
Generic Literal Methods​
is_a?(STRING)​
Returns
BOOLEAN|ERROR
Returns true when the value is of the given type or belongs to the given type group, so one question covers both. The name has to be one that exists: anything else is an error rather than a false, because a typo would otherwise read as a real answer. See Types and type groups.
nil.is_a?("NIL")
"a".is_a?("HASHABLE")
nil.is_a?("HASHABLE")
true.is_a?("INTEGERABLE")
"a".is_a?("INTEGER")
true
true
false
true
false
methods()​
Returns
ARRAY
Returns the names of the methods specific to this literal type, not including the generic methods listed on this page. The names are sorted, so the result is the same on every run. A type with no methods of its own returns an empty array.
1.0.methods().include?("round")
true.methods()
true
[]
nil?()​
Returns
BOOLEAN
Returns true only for nil. Reads better than comparing against nil at the end of a chain, and every type answers it.
nil.nil?()
1.nil?()
"".nil?()
[].first().nil?()
true
false
false
true
to_f()​
Returns
FLOAT|NIL
Converts an object to its float representation, or nil when it cannot. A nil result is what distinguishes a failed conversion from a genuine 0.0.
1.to_f()
"1.4".to_f()
"abc".to_f()
nil.to_f()
1.0
1.4
nil
nil
to_i()​
Returns
INTEGER|NIL
Converts an object to its integer representation, or nil when it cannot. A nil result is what distinguishes a failed conversion from a genuine 0. For strings a 0b, 0o or 0x prefix selects binary, octal or hexadecimal and is matched case insensitively, a leading zero followed only by octal digits is octal, and anything else is decimal. The resulting integer keeps the base it was parsed with, and integers of differing bases cannot be combined directly.
true.to_i()
false.to_i()
1234.to_i()
"4".to_i()
"0".to_i()
"0125".to_i()
"0x2322".to_i()
"0b1010".to_i()
"test".to_i()
1
0
1234
4
0
0o125
0x2322
0b1010
nil
to_json()​
Returns
STRING|ERROR
Returns the object as json notation.
a = {"test": 1234}
a.to_json()
{"test": 1234}
"{\"test\":1234}"
to_s()​
Returns
STRING
Converts an object to its string representation, or the empty string when it has none. Takes no arguments; an integer renders in its own base, so use to_base first to change it.
true.to_s()
1234.to_s()
"test".to_s()
1.4.to_s()
nil.to_s()
"0b1010".to_i().to_s()
"true"
"1234"
"test"
"1.4"
""
"0b1010"
type()​
Returns
STRING
Returns the type of the object.
"test".type()
"STRING"
type_groups()​
Returns
ARRAY
Returns the type groups the value belongs to, sorted. ANY is not listed: every value belongs to it, so it would say nothing while prefixing every answer. It exists for signatures, where push(ANY) means the argument accepts anything, and is_a?("ANY") still answers true. See Types and type groups for what each group means.
1.type_groups()
nil.type_groups()
def() end.type_groups()
puts.type_groups()
["COMPARABLE", "HASHABLE", "INTEGERABLE", "NUMERIC", "STRINGABLE"]
["STRINGABLE"]
["CALLABLE"]
["CALLABLE"]
wat()​
Returns
NIL
Prints the type's literal-specific methods with their argument and return types, sorted by name, one per line. It returns nil rather than the listing: this exists to be read, and the REPL echoes a returned value through its escaped representation, which would put the whole thing on one line. Use methods when the names are wanted as data. A type with no methods of its own prints only the heading.
true.wat()
1.0.wat()
BOOLEAN supports the following methods:
nil
FLOAT supports the following methods:
abs()
ceil([INTEGER])
divmod(FLOAT)
finite?()
floor([INTEGER])
infinite?()
nan?()
negative?()
positive?()
round([INTEGER])
truncate([INTEGER])
zero?()
nil