# Constants¶

NumPy includes several constants:

- numpy.Inf¶
IEEE 754 floating point representation of (positive) infinity.

Use

`inf`

because`Inf`

,`Infinity`

,`PINF`

and`infty`

are aliases for`inf`

. For more details, see`inf`

.See Also

inf

- numpy.Infinity¶
IEEE 754 floating point representation of (positive) infinity.

Use

`inf`

because`Inf`

,`Infinity`

,`PINF`

and`infty`

are aliases for`inf`

. For more details, see`inf`

.See Also

inf

- numpy.NAN¶
IEEE 754 floating point representation of Not a Number (NaN).

`NaN`

and`NAN`

are equivalent definitions of`nan`

. Please use`nan`

instead of`NAN`

.See Also

nan

- numpy.NINF¶
IEEE 754 floating point representation of negative infinity.

Returns

- yfloat
A floating point representation of negative infinity.

See Also

isinf : Shows which elements are positive or negative infinity

isposinf : Shows which elements are positive infinity

isneginf : Shows which elements are negative infinity

isnan : Shows which elements are Not a Number

isfinite : Shows which elements are finite (not one of Not a Number, positive infinity and negative infinity)

Notes

NumPy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). This means that Not a Number is not equivalent to infinity. Also that positive infinity is not equivalent to negative infinity. But infinity is equivalent to positive infinity.

Examples

>>> np.NINF -inf >>> np.log(0) -inf

- numpy.NZERO¶
IEEE 754 floating point representation of negative zero.

Returns

- yfloat
A floating point representation of negative zero.

See Also

PZERO : Defines positive zero.

isinf : Shows which elements are positive or negative infinity.

isposinf : Shows which elements are positive infinity.

isneginf : Shows which elements are negative infinity.

isnan : Shows which elements are Not a Number.

- isfiniteShows which elements are finite - not one of
Not a Number, positive infinity and negative infinity.

Notes

NumPy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). Negative zero is considered to be a finite number.

Examples

>>> np.NZERO -0.0 >>> np.PZERO 0.0

>>> np.isfinite([np.NZERO]) array([ True]) >>> np.isnan([np.NZERO]) array([False]) >>> np.isinf([np.NZERO]) array([False])

- numpy.NaN¶
IEEE 754 floating point representation of Not a Number (NaN).

`NaN`

and`NAN`

are equivalent definitions of`nan`

. Please use`nan`

instead of`NaN`

.See Also

nan

- numpy.PINF¶
IEEE 754 floating point representation of (positive) infinity.

Use

`inf`

because`Inf`

,`Infinity`

,`PINF`

and`infty`

are aliases for`inf`

. For more details, see`inf`

.See Also

inf

- numpy.PZERO¶
IEEE 754 floating point representation of positive zero.

Returns

- yfloat
A floating point representation of positive zero.

See Also

NZERO : Defines negative zero.

isinf : Shows which elements are positive or negative infinity.

isposinf : Shows which elements are positive infinity.

isneginf : Shows which elements are negative infinity.

isnan : Shows which elements are Not a Number.

- isfiniteShows which elements are finite - not one of
Not a Number, positive infinity and negative infinity.

Notes

NumPy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). Positive zero is considered to be a finite number.

Examples

>>> np.PZERO 0.0 >>> np.NZERO -0.0

>>> np.isfinite([np.PZERO]) array([ True]) >>> np.isnan([np.PZERO]) array([False]) >>> np.isinf([np.PZERO]) array([False])

- numpy.e¶
Euler’s constant, base of natural logarithms, Napier’s constant.

`e = 2.71828182845904523536028747135266249775724709369995...`

See Also

exp : Exponential function log : Natural logarithm

References

- numpy.euler_gamma¶
`γ = 0.5772156649015328606065120900824024310421...`

References

- numpy.inf¶
IEEE 754 floating point representation of (positive) infinity.

Returns

- yfloat
A floating point representation of positive infinity.

See Also

isinf : Shows which elements are positive or negative infinity

isposinf : Shows which elements are positive infinity

isneginf : Shows which elements are negative infinity

isnan : Shows which elements are Not a Number

isfinite : Shows which elements are finite (not one of Not a Number, positive infinity and negative infinity)

Notes

NumPy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). This means that Not a Number is not equivalent to infinity. Also that positive infinity is not equivalent to negative infinity. But infinity is equivalent to positive infinity.

`Inf`

,`Infinity`

,`PINF`

and`infty`

are aliases for`inf`

.Examples

>>> np.inf inf >>> np.array([1]) / 0. array([ Inf])

- numpy.infty¶
IEEE 754 floating point representation of (positive) infinity.

Use

`inf`

because`Inf`

,`Infinity`

,`PINF`

and`infty`

are aliases for`inf`

. For more details, see`inf`

.See Also

inf

- numpy.nan¶
IEEE 754 floating point representation of Not a Number (NaN).

Returns

y : A floating point representation of Not a Number.

See Also

isnan : Shows which elements are Not a Number.

isfinite : Shows which elements are finite (not one of Not a Number, positive infinity and negative infinity)

Notes

NumPy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). This means that Not a Number is not equivalent to infinity.

`NaN`

and`NAN`

are aliases of`nan`

.Examples

>>> np.nan nan >>> np.log(-1) nan >>> np.log([-1, 1, 2]) array([ NaN, 0. , 0.69314718])

- numpy.newaxis¶
A convenient alias for None, useful for indexing arrays.

Examples

>>> newaxis is None True >>> x = np.arange(3) >>> x array([0, 1, 2]) >>> x[:, newaxis] array([[0], [1], [2]]) >>> x[:, newaxis, newaxis] array([[[0]], [[1]], [[2]]]) >>> x[:, newaxis] * x array([[0, 0, 0], [0, 1, 2], [0, 2, 4]])

Outer product, same as

`outer(x, y)`

:>>> y = np.arange(3, 6) >>> x[:, newaxis] * y array([[ 0, 0, 0], [ 3, 4, 5], [ 6, 8, 10]])

`x[newaxis, :]`

is equivalent to`x[newaxis]`

and`x[None]`

:>>> x[newaxis, :].shape (1, 3) >>> x[newaxis].shape (1, 3) >>> x[None].shape (1, 3) >>> x[:, newaxis].shape (3, 1)

- numpy.pi¶
`pi = 3.1415926535897932384626433...`

References