Is it a whole number?

Question

A number is whole if it is a non-negative integer with no decimal part. So 0 and 8 and 233494.0 are whole, while 1.1 and 0.001 and 233494.999 are not.

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Input

A floating-point number in the default base/encoding of your language.

For example, the default integer representation for Binary Lambda Calculus would be Church numerals. But the default integer representation for Python is base 10 decimal, not Unary.

Output

A truthy value if the input is whole, a falsy value if it is not.

Note that if your language only supports decimal precision to, say, 8 places, 1.000000002 can be considered whole.

Input and output may be done via any standard I/O methods.

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Test cases

Input        -> Output
332          -> true
33.2         -> false
128239847    -> true
0.128239847  -> false
0            -> true
0.000000000  -> true
1.111111111  -> false
-3.1415926   -> false
-3           -> false

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Scoring

As with code-golf, the shortest submission wins. Good luck!

Answer 1

Lua, 38 bytes

function f(n)print(n>=0 and n%1==0)end

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Answer 2

REXX, 27 bytes

arg n
say trunc(n)=n & n>=0

Answer 3

Kotlin, 17 bytes

{it%1==.0&&it>=0}

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Answer 4

C + ecpp, 23 bytes

#def $x !fmod(x,1)&x>=0

Defines an operator $ that takes one right operand x and evaluates to 1 if x is whole and 0 if it is not.

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Answer 5

C on Linux, 31 bytes

int f(float v){return!rintf(v);}

The correct prototype for rintf is float rintf(float). However, in IEEE floating-point, 0.0f has the binary representation of all zeros. We (mis)use this feature to get away without using a prototype; the zero/non-zero value is then inverted into 1 or 0.

Answer 6

Pyth, 4 bytes

Not a difficult question, but I thought I’d give it a try. Also did not think that zero was whole, but it saves a byte.

qs.a

Explanation:

 s.a      Integer of the absolute value of the implicit input
q         Is it the same as the original implicit input?

Test Suite

Version that doesn’t find 0 as a whole number:

&qs.a

Ands the original answer with the input, so 0 falsifies the answer.

Test Suite

Returns a falsy or truthy value that isn’t always a Boolean.

Answer 7

Julia, 13 bytes

f(x)=x in 0:x

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Answer 8

D, 36 33 30 bytes

T f(T)(T n){return(n<0)==n%1;}

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I will not be beaten in D!

Answer 9

Taxi, 553 bytes

Go to Post Office:w 1 l 1 r 1 l.Pickup a passenger going to The Babelfishery.Go to The Babelfishery:s 1 l 1 r.Pickup a passenger going to Cyclone.Go to Cyclone:n 5 l 2 l.Pickup a passenger going to Trunkers.Pickup a passenger going to Equal's Corner.Go to Trunkers:s 1 l.Pickup a passenger going to Equal's Corner.Go to Equal's Corner:w 1 l.Switch to plan "b" if no one is waiting.'1' is waiting at Writer's Depot.[b]'0' is waiting at Writer's Depot.Go to Writer's Depot:n 1 l 1 r.Pickup a passenger going to Post Office.Go to Post Office:n 1 r 2 r 1 l.

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Ungolfed:

Go to Post Office: west 1st left 1st right 1st left.
Pickup a passenger going to The Babelfishery.
Go to The Babelfishery: south 1st left 1st right.
Pickup a passenger going to Cyclone.
Go to Cyclone: north 5th left 2nd left.
Pickup a passenger going to Trunkers.
Pickup a passenger going to Equal's Corner.
Go to Trunkers: south 1st left.
Pickup a passenger going to Equal's Corner.
Go to Equal's Corner: west 1st left.
Switch to plan "b" if no one is waiting.
'1' is waiting at Writer's Depot.
[b]
'0' is waiting at Writer's Depot.
Go to Writer's Depot: north 1st left 1st right.
Pickup a passenger going to Post Office.
Go to Post Office: north 1st right 2nd right 1st left.

I'm surprised it took this long to post such a basic challenge. I like them. Taxi is... still not good for golfing.

Answer 10

Jelly, 3 bytes

Ḟ⁼A

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Uses Erik's strategy of floor(n) == abs(n).

Answer 11

Jelly, 3 bytes

AḞ=

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Answer 12

Pyt, 3 4 bytes

Đ⎶Å≡

    implicit input
Đ   duplicates top value
⎶   pushes closest int to top value
Å   abs(TOS)
≡   checks if equal
    implicit output

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Answer 13

SNOBOL4 (CSNOBOL4), 73 bytes

	DEFINE('W(N)D')
W	N SPAN('1234567890') '.' REM . D
	W =EQ(D) 1	:(RETURN)

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An anonymous function; returns 1 for truthy and an empty string for falsey.

Takes N the input and matches it against the regex \\d.(\\d*)$, setting (\\d*) as D. Then if D==0 (''==0 in SNOBOL), sets W to 1. If not, it doesn't set W, which defaults to the empty string, and returns W.

Answer 14

Javascript - 16 Bytes

a=>a>=0&&a%1<=0

f=a=>a>=0&&a%1<=0

// ----------- Test Cases -------------

console.log(332, f(332))
console.log(33.2, f(33.2))
console.log(128239847, f(128239847))
console.log(0.128239847, f(0.128239847))
console.log(0, f(0))
console.log(0.000000000, f(0.000000000))
console.log(1.111111111, f(1.111111111))
console.log(-3.1415926, f(-3.1415926))
console.log(-3, f(-3))

Answer 15

TI-BASIC, 5 bytes

Takes input and gives output through Ans.

Ans=abs(int(Ans

Answer 16

JavaScript (SpiderMonkey), 24 bytes

s=>s<0?0:s==Math.ceil(s)

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A great thanks to @Jo King for converting the code from 29bytes to 24.

Answer 17

MathGolf, 3 bytes

i±=

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Explanation

Same as a bunch of other answers.

i     Read input as integer
 ±    Convert to absolute value
  =   Is it equal to the implicit input?

Answer 18

Python 2, 59 60 57 bytes

lambda s:re.match(r"^\+?[0-9]+(\.0*)?$",s)>None
import re

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Takes input as a string.

Regex is as follows:

• starts with + or a number
• has AT LEAST 1 digit
• either:
  • has a period, but only zeroes follow the period
  • has a period, but nothing after the period
  • terminates without a period

Python 2's re.match objects are greater than None objects, so it will return True if the regex matched and False otherwise.

Edit: no longer has false positives on negative numbers (not sure what i was thinking...) and correctly handles trailing periods. Thanks, Deadcode!

^{_{I feel so bad about the greater than None check.}}

Answer 19

Gol><>, 17 bytes

I:0(q0h:S(-zq1!0h

A simple solution, but I will be golfing this alot more

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Answer 20

cQuents, 4 bytes

?$-1

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Explanation

?        Given input n, output true if n is in the sequence and false if it is not
         Each term in the sequence equals
 $        current index
  -1                    - 1

The -1 in to include 0 - if the challenge just wanted positive integers, ?$ would be enough.

Answer 21

Runic Enchantments, 6 bytes

i:kn=@

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Works on inputs up to 65535. Compares the input with the input cast to character and back to number. Inputs larger than 65535 cast to char exceed the byte size and roll over.

Answer 22

Stax, 2 bytes

1%

Run and debug it

Modulus by 1.

Answer 23

ARBLE, 9 7 bytes

nt(a%1)

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