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Implement float is_integer method #112

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Merged
merged 3 commits into from
Oct 5, 2019
Merged

Implement float is_integer method #112

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318fec0
Implement float is_integer method
DoDaek Oct 2, 2019
d78d515
float: modified is_integer method
DoDaek Oct 4, 2019
3b0574d
float: modified return values of is_integer method
DoDaek Oct 4, 2019
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Implement float is_integer method
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@DoDaek
DoDaek committed Oct 2, 2019
commit 318fec0eb9eac51a299c27cf18c6d2f3814f6ae0
15 changes: 15 additions & 0 deletions py/float.go
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Original file line number Diff line number Diff line change
Expand Up @@ -394,6 +394,21 @@ func (a Float) M__ge__(other Object) (Object, error) {
return NotImplemented, nil
}

// Properties
func init() {
FloatType.Dict["is_integer"] = MustNewMethod("is_integer", func(self Object) (Object, error) {
if a, ok := convertToFloat(self); ok {
f, err := FloatAsFloat64(a)
if err != nil {
return nil, err
}
b := math.Abs(f - math.Round(f))
return NewBool(b < math.SmallestNonzeroFloat64), nil;
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@corona10 corona10 Oct 3, 2019 •
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Is there any reason to use this logic?
CPython check the float is an integer by using the floor API.

 o = (floor(x) == x) ? Py_True : Py_False;

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@DoDaek DoDaek Oct 3, 2019 •
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Calculating the difference between rounded value and original value.
If the difference is less than the minimum value of float64, I think that it would be an integer.

I'll check the Cpython and then fix that part by using floor API.

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FYI, https://github.com/python/cpython/blob/279f44678c8b84a183f9eeb85e0b086228154497/Objects/floatobject.c#L853

}
return nil, AttributeError
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@corona10 corona10 Oct 3, 2019 •
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return nil, cantConvert(a, "float")

might be better

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I'll change that part with cantConvert method.

}, 0, "is_integer() -> Return True if the float instance is finite with integral value, and False otherwise.")
}

// Check interface is satisfied
var _ floatArithmetic = Float(0)
var _ conversionBetweenTypes = Float(0)
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4 changes: 4 additions & 0 deletions py/tests/float.py
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Expand Up @@ -34,4 +34,8 @@
assert str(float("1.00")) == "1.0"
assert str(float("2.010")) == "2.01"

doc="is_integer"
assert (1.0).is_integer() == True
assert (2.3).is_integer() == False

doc="finished"