Mathematical Operations on Array

[Peter Otten]

Bryan.Fodness at gmail.com wrote:

> I am loading text into an array and would like to convert the values.
> 
> from math import *
> from numpy import *
> from pylab import *
> 
> data=loadtxt('raw.dat')
> mincos=degrees(acos(data[:,0]))
> minazi=degrees(data[:,1])
> minthick=data[:,2]/0.006858
> 
> I am not sure why degrees()  works, but acos() does not.
> 
> I receive the following
> 
> Traceback (most recent call last):
>   File "C:\ test.py", line 6, in ?
>     mincos=degrees(acos(float(data[:,0])))
> TypeError: only length-1 arrays can be converted to Python scalars
> 
> Can anyone tell me what I am doing wrong?

Using star-imports. 

Among other things it makes it hard to keep track of where things are coming 
from:

>>> from math import *
>>> from numpy import *
>>> degrees
<ufunc 'degrees'>
>>> acos
<built-in function acos>
>>> acos.__module__
'math'
>>> arccos
<ufunc 'arccos'>