Question

这似乎工作正常 -

%time a = "abc"
print(a)

CPU times: user 0 ns, sys: 0 ns, total: 0 ns
Wall time: 19.1 µs
abc

这不是 -

def func():
    %time b = "abc"
    print(b)

func()

CPU times: user 0 ns, sys: 0 ns, total: 0 ns
Wall time: 31 µs
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-8-57f7d48952b8> in <module>()
      3     print(b)
      4 
----> 5 func()

<ipython-input-8-57f7d48952b8> in func()
      1 def func():
      2     get_ipython().magic(u'time b = "abc"')
----> 3     print(b)
      4 
      5 func()

NameError: global name 'b' is not defined

这是指向notebook

的链接

我使用的是python 2.7，但尚未尝试使用python3。

这是预期的行为吗？

Answer 1

我几乎可以肯定这是一个IPython错误。 Reported here

In [31]: def func():
    ...:     a = 2
    ...:     %time b = 1
    ...:     print(locals())
    ...:     print a
    ...:     print b

In [32]: func()
CPU times: user 3 µs, sys: 0 ns, total: 3 µs
Wall time: 6.2 µs
{'a': 2, 'b': 1}
2
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-32-08a2da4138f6> in <module>()
----> 1 func()

<ipython-input-31-13da62c18a7e> in func()
      4     print(locals())
      5     print a
----> 6     print b
      7
      8

NameError: global name 'b' is not defined

Answer 2

如果你在等号之后写%time，它可以在Python 3中运行，如下所示：

def func():
    a = 2
    b = %time 1
    print(locals())
    print(a)
    print(b)

func()

输出：

CPU times: user 6 µs, sys: 0 ns, total: 6 µs
Wall time: 10.3 µs
{'a': 2, 'b': 1}
2
1

语句后面的％time语句中定义的变量不可访问

2 个答案: