Dumb python questions

[Richard Jones]

On Wednesday 15 August 2001 15:59, Paul Rubin wrote:
> I just started playing with python and haven't been able to figure
> out the following things from the docs I've found:
>
> 1) Suppose I have a complex number like a = 3+4j.  How do I get the
> real and imaginary parts separately?  I guess I could say
>    x = (a + a.conjugate())/2
>    y = (a - a.conjugate())/2
> but I can't take this language seriously if that's what the designers
> intended.

>>> a = 1 + 2j
>>> dir(a)
['conjugate', 'imag', 'real']
>>> a.imag
2.0
>>> a.real
1.0

See also the manual - the tutorial covers this in the Numbers section. The 
library reference covers this in the Numbers section of the builtin types 
section.


> 2) Is there a way I can tell if a value is of an integer type?  That is,
>    I want to write a function is_int(x) so that
>      is_int(3) = 1    # 3 is an integer type
>      is_int(3L) = 1   # 3L is an integer type
>      is_int(3.0) = 0  # 3.0 is float type
>      is_int(3+2j) = 0 # 3+2j is complex type

  "type(value) == IntType"
  "type(value) == type(1)"

See the manual under builtin functions, or the types module.


> 3) Are the complex math functions specified to have any particular
>    branch cuts?  If they're unspecified, what happens in the actual cmath
>    implementation?  If they're unspecified, I'd like to propose that the
>    Scheme/Common Lisp conventions be adopted in a future version.

This one I can't help you with as I can't recall what a "branch cut" is.


    Richard