IsEven

Whether n is an even integer.

✓ checked against that system · ! checked, with disagreements (hover a chip)Fungrim entry1c3766↗28b4c3↗64f0a5↗c0e088✓↗fd732d✓↗Wolfram LanguageEvenQ!↗

IsEven(n)$True$ if $n$ is an even integer, else $False$.

Juliais_even(ZZ(n))Rustis_even(n)

Typed signatures

Type	Package	Applies
(number) -> boolean	compute-engine	always

Domain: Arithmetic

Examples

Basic #

live ↗

In$\mathrm{IsEven}(4)$Out$\mathrm{True}$

live ↗

In$\mathrm{IsEven}(3)$Out$\mathrm{False}$

Zero is even

live ↗

In$\mathrm{IsEven}(0)$Out$\mathrm{True}$

Negative integers count too

live ↗

In$\mathrm{IsEven}(-4)$Out$\mathrm{True}$

An even integer gives True

live ↗

In$\mathrm{IsEven}(8)$Out$\mathrm{True}$

Scope #

A non-integer is not even

live ↗

In$\mathrm{IsEven}(2.5)$Out$\mathrm{False}$

Big integers

live ↗

In$\mathrm{IsEven}(2^{100})$Out$\mathrm{True}$

live ↗

In$\mathrm{IsEven}(10!)$Out$\mathrm{True}$

Threads element-wise over a list

live ↗

In$\mathrm{IsEven}(\bigl\lbrack1, 2, 3\bigr\rbrack)$Out$\bigl\lbrack\mathrm{False}, \mathrm{True}, \mathrm{False}\bigr\rbrack$

Applications #

Select the even numbers up to 10

live ↗

In$\mathrm{Filter}(1..10, \mathrm{IsEven})$Out$\bigl\lbrack2, 4, 6, 8, 10\bigr\rbrack$

Properties #

Every integer is exactly one of odd and even. See IsOdd

live ↗

In$\mathrm{IsOdd}(12)\veebar\mathrm{IsEven}(12)$Out$\mathrm{True}$

Divisible by 2, so even

live ↗

In$\mathrm{IsEven}(12)$Out$\mathrm{True}$

Possible issues #

A symbol stays undecided rather than False

live ↗

In$\mathrm{IsEven}(x)$Out$\mathrm{IsEven}(x)$

About

Examples	13
Checked against	Wolfram Language 12 agree1 differSymPy 10 agree1 differJulia 9 agree1 errorRust 8 agree2 error
Crosswalk	Fungrim entry ×5Wolfram LanguageJuliaRust

Implementation

mappedsympypackages/oracle/src/mappings.ts

Wolfram's EvenQ is False unless the operand is an even integer, so SymPy's undecided is_even (None), as for a symbol or 4.0, reads as False.

mappedjuliapackages/oracle/src/mappings.ts

mappedrustpackages/oracle/src/mappings.ts

See also: IsOdd