Question

I am new to Python and I am trying to write a simple print function but I am getting a strange error. This is my code:

#! /usr/bin/env python3.2
import numpy as np

a=np.arange(1,10,1)
print(a)
for i in a:
    print(i)
    print(type(i))
    print("{0:<12g}".format(i))

The output is:

[1 2 3 4 5 6 7 8 9]
1
<class 'numpy.int64'>
Traceback (most recent call last):
  File "./test.py", line 9, in <module>
    print("{0:<12g}".format(i))
ValueError: Unknown format code 'g' for object of type 'str'

Why does print take the “numpy.int64” as a string? I have to add that it works perfectly for a normal list: (e.g. [1,2,3,4]) I would be most grateful to any ideas on this issue, thanks ;-).

Answer 1

This is a known bug and should be fixed in version 2.0. In the interim, you can use the old syntax %f that works.