python Decimal - checking if integer

Try math.floor(val) == val or val == int(val).

You could use the modulo operation to check if there is a non-integer remainder:

>>> from decimal import Decimal
>>> Decimal('3.14') % 1 == 0
False
>>> Decimal('3') % 1 == 0
True
>>> Decimal('3.0') % 1 == 0
True

The mathematical solution is to convert your decimal number to integer and then test its equality with your number.

Since Decimal can have an arbitrary precision, you should not convert it to int or float.

Fortunately, the Decimalclass has a to_integral_value which make the conversion for you. You can adopt a solution like this:

def is_integer(d):
    return d == d.to_integral_value()

Example:

from decimal import Decimal

d_int = Decimal(3)
assert is_integer(d_int)

d_float = Decimal(3.1415)
assert not is_integer(d_float)

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