ValueError:类型为"str"的对象的未知格式代码"g" [英] ValueError: Unknown format code 'g' for object of type 'str'

问题描述

我是Python的新手，我试图编写一个简单的打印函数，但遇到一个奇怪的错误.这是我的代码:

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))

输出为:

[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'

为什么打印将"numpy.int64"作为字符串?我必须补充一点，它非常适合普通列表:(例如[1,2,3,4])，感谢您对这个问题的任何想法，谢谢;-).

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 ;-).

推荐答案

这是已知错误，并且应在2.0版中进行修复.在此期间，您可以使用有效的旧语法%f.

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.

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