numpy – Python AttributeError: function object has no attribute min

numpy – Python AttributeError: function object has no attribute min

If this line

new_x = np.linspace(x.min(), x.max(), new_length)

is generating the error message

AttributeError: function object has no attribute min

then x is a function, and functions (in general) dont have min attributes, so you cant call some_function.min(). What is x? In your code, youve only defined it as

x=var

Im not sure what var is. var isnt a default builtin in Python, but if its a function, then either youve defined it yourself for some reason or youve picked it up from somewhere (say youre using Sage, or you did a star import like from sympy import * or something.)

[Update: since you say youre using PyLab, probably var is numpy.var which has been imported into scope at startup in IPython. I think you really mean using IPython in --pylab mode.]

You also define x1 and y1, but then your later code refers to x and y, so it sort of feels like this code is halfway between two functional states.

Now numpy arrays do have a .min() and .max() method, so this:

>>> x = np.array([0.1, 0.3, 0.4, 0.7])
>>> y = np.array([0.2, 0.5, 0.6, 0.9])
>>> new_length = 25
>>> new_x = np.linspace(x.min(), x.max(), new_length)
>>> new_y = sp.interpolate.interp1d(x, y, kind=cubic)(new_x)

would work. Your test data wont because the interpolation needs at least 4 points, and youd get

ValueError: x and y arrays must have at least 4 entries

Second question: how do I input more than one line of code at once? At the moment, if I try to copy the whole thing and then paste it into PyLab, it only inputs the top line of my code, so I have to paste the whole thing in one line at a time. How do I get round this?

Assuming youre in ipython called as ipython --pylab or something similar, then you can simply use the paste magic command. Call it as %paste or simply paste if you havent defined paste as another variable:

In [8]: paste
import numpy as np
import scipy as sp
from scipy.interpolate import interp1d

x=var
x1 = ([0.1,0.3,0.4])
y1 = [0.2,0.5,0.6]

new_length = 25
new_x = np.linspace(x.min(), x.max(), new_length)
new_y = sp.interpolate.interp1d(x, y, kind=cubic)(new_x)

## -- End pasted text --
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-8-b4e41f59d719> in <module>()
      3 from scipy.interpolate import interp1d
      4 
----> 5 x=var
      6 x1 = ([0.1,0.3,0.4])
      7 y1 = [0.2,0.5,0.6]

NameError: name var is not defined

In [9]: 

numpy – Python AttributeError: function object has no attribute min

Change that line to:

new_x = np.linspace(min(x), max(x), new_length)

min and max are not attributes of lists, they are their own functions.