Numpy > TypeError: iteration over a 0-d array > 要素が１つの時にndimが0になる場合がある > 対処

動作環境

GeForce GTX 1070 (8GB)
ASRock Z170M Pro4S [Intel Z170chipset]
Ubuntu 16.04 LTS desktop amd64
TensorFlow v1.2.1
cuDNN v5.1 for Linux
CUDA v8.0
Python 3.5.2
IPython 6.0.0 -- An enhanced Interactive Python.
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
GNU bash, version 4.3.48(1)-release (x86_64-pc-linux-gnu)
scipy v0.19.1
geopandas v0.3.0
MATLAB R2017b (Home Edition)

Error

test_0-d_array_171203.py

import numpy as np


ain = 1
wrk = np.log(1) / np.log(2)
xs = np.array(wrk)
print(xs.ndim)

for elem in xs:
    print(elem)

run

$ python3 test_0-d_array_171203.py 
0
Traceback (most recent call last):
  File "test_0-d_array_171203.py", line 9, in <module>
    for elem in xs:
TypeError: iteration over a 0-d array

log同士の除算などの場合でndimが0になる場合があるようだ。

対処

以下で対処する。

test_0-d_array_171203.py

import numpy as np


ain = 1
wrk = np.log(1) / np.log(2)
xs = np.array(wrk)
print(xs.ndim)

if xs.ndim == 0:
    xs = [xs]

for elem in xs:
    print(elem)

run

$ python3 test_0-d_array_171203.py 
0
0.0