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isLessThanOrEqualTo(_:)

Returns a Boolean value indicating whether this instance is less than or equal to the given value.

Declaration

func isLessThanOrEqualTo(_ other: Double) -> Bool

Parameters

  • other:

    The value to compare with this value.

Return Value

true if other is greater than this value; otherwise, false. If either this value or other is NaN, the result of this method is false.

Discussion

This method serves as the basis for the less-than-or-equal-to operator (<=) for floating-point values. Some special cases apply:

  • Because NaN is incomparable with any value, this method returns false when called on NaN or when NaN is passed as other.

  • -infinity compares less than or equal to all values except NaN.

  • Every value except NaN compares less than or equal to +infinity.

The following example shows the behavior of the isLessThanOrEqualTo(_:) method with different kinds of values:

let x = 15.0
x.isLessThanOrEqualTo(20.0)
// true
x.isLessThanOrEqualTo(.nan)
// false
Double.nan.isLessThanOrEqualTo(x)
// false

The isLessThanOrEqualTo(_:) method implements the less-than-or-equal predicate defined by the IEEE 754 specification.

See Also

Comparing Values