# Mathematical Operations on Array

Discussion in 'Python' started by Bryan.Fodness@gmail.com, Apr 1, 2011.

1. ### Guest

I am loading text into an array and would like to convert the values.

from math import *
from numpy import *
from pylab import *

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.

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?

, Apr 1, 2011

2. ### Peter OttenGuest

wrote:

> I am loading text into an array and would like to convert the values.
>
> from math import *
> from numpy import *
> from pylab import *
>
> 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.
>
>
> 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'>

Peter Otten, Apr 1, 2011

3. ### Guest

On Apr 1, 9:52 am, Peter Otten <> wrote:
> wrote:
> > I am loading text into an array and would like to convert the values.

>
> > from math import *
> > from numpy import *
> > from pylab import *

>
> > 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'>- Hide quoted text -
>
> - Show quoted text -

Thank you.

, Apr 1, 2011
4. ### Terry ReedyGuest

On 4/1/2011 9:35 AM, wrote:

> Can anyone tell me what I am doing wrong?

Posting the same question twice is a bad idea, as it splits answers and