[Numpy-discussion] cos -- NameError: global name 'cos' is not defined

Wayne Watson sierra_mtnview@sbcglobal....
Mon Dec 21 17:11:41 CST 2009

Yes, thanks. That's the what I finally changed to. This originated up a 
thread or so when I displayed the highly populated code with math. Some 
said I didn't need it, so I thought I'd give it a go.

I just started plugging away again with IDLE and am pretty convinced 
that IDLE is something of an enemy. I started afresh loading this into 
the editor:

    import math
    print "hello, math world."
    print math.cos(0.5)
    print math.sin(0.8)

Run works fine. No errors. Now I do:
 >>> dir()
['__builtins__', '__doc__', '__file__', '__name__', 'idlelib', 'math']
OK, swell. Now I import via the script window
 >>> import numpy as np
 >>> dir()
['__builtins__', '__doc__', '__file__', '__name__', 'idlelib', 'math', 'np']

I think I'm adding to the namespace both the program the script sees., 
because adding this ref to np in the program works fine.

    import math
    print "hello, math world."
    print math.cos(0.5)
    print math.sin(0.8)
    print np.sin(2.2)

I've been assuming that IDLE clears the namespace.  It's quite possible 
that I get anomalous results as I move between Run the program via the 
editor, and fiddling in script land. I would like to think that IDLE has 
some way to clear the namespace before it runs the program. If not, yikes!

Robert Kern wrote:
> On Mon, Dec 21, 2009 at 11:40, Wayne Watson
> <sierra_mtnview@sbcglobal.net> wrote:
>> In this code,
>> ===========start
>> import math
>> import numpy as np
>> from numpy import matrix
>> def sinD(D): # given in degrees, convert to radians
>>    return sin(radians(D))
>> def cosD(D):
>>    return cos(radians(D))   <<--------------
>> def acosD(D):
>>    acos(radians(D))
>>    return=====end
>> the << line produces, "NameError: global name 'cos' is not defined", but
>> the sin() above it does not? They are both built-in functions.
> No, they aren't. They are in the math module. You want math.cos(). The
> same goes for radians() and acos() and sin().

           Wayne Watson (Watson Adventures, Prop., Nevada City, CA)

             (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
              Obz Site:  39° 15' 7" N, 121° 2' 32" W, 2700 feet  
             "... humans'innate skills with numbers isn't much
              better than that of rats and dolphins." 
                       -- Stanislas Dehaene, neurosurgeon 
                    Web Page: <www.speckledwithstars.net/>

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