这是一个float型的常数

>>> cmath.e

2.718281828459045

>>> type(cmath.e)

文档

>>> import cmath

>>> help(cmath)

Help on module cmath:

NAME

cmath

FILE

/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/cmath.so

MODULE DOCS

http://docs.python.org/library/cmath Go

DESCRIPTION

This module is always available. It provides access to mathematical

functions for complex numbers.

FUNCTIONS

acos(...)

acos(x)

Return the arc cosine of x.

acosh(...)

acosh(x)

Return the inverse hyperbolic cosine of x.

asin(...)

asin(x)

Return the arc sine of x.

asinh(...)

asinh(x)

Return the inverse hyperbolic sine of x.

atan(...)

atan(x)

Return the arc tangent of x.

atanh(...)

atanh(x)

Return the inverse hyperbolic tangent of x.

cos(...)

cos(x)

Return the cosine of x.

cosh(...)

cosh(x)

Return the hyperbolic cosine of x.

exp(...)

exp(x)

Return the exponential value e**x.

isinf(...)

isinf(z) -> bool

Checks if the real or imaginary part of z is infinite.

isnan(...)

isnan(z) -> bool

Checks if the real or imaginary part of z not a number (NaN)

log(...)

log(x[, base]) -> the logarithm of x to the given base.

If the base not specified, returns the natural logarithm (base e) of x.

log10(...)

log10(x)

Return the base-10 logarithm of x.

phase(...)

phase(z) -> float

Return argument, also known as the phase angle, of a complex.

polar(...)

polar(z) -> r: float, phi: float

Convert a complex from rectangular coordinates to polar coordinates. r is

the distance from 0 and phi the phase angle.

rect(...)

rect(r, phi) -> z: complex

Convert from polar coordinates to rectangular coordinates.

sin(...)

sin(x)

Return the sine of x.

sinh(...)

sinh(x)

Return the hyperbolic sine of x.

sqrt(...)

sqrt(x)

Return the square root of x.

tan(...)

tan(x)

Return the tangent of x.

tanh(...)

tanh(x)

Return the hyperbolic tangent of x.

DATA

e = 2.718281828459045

pi = 3.141592653589793

>>>