问题描述
我有一个array
,如下所示
np.array(["hello","world",{"a":5,"b":6,"c":8},"usa","india",{"d":9,"e":10,"f":11}])
和如下所示的pandas
DataFrame
df = pd.DataFrame({'A': ["hello","world",{"a":5,"b":6,"c":8},"usa","india",{"d":9,"e":10,"f":11}]})
当我将np.isreal
应用于DataFrame
df.applymap(np.isreal)
Out[811]:
A
0 False
1 False
2 True
3 False
4 False
5 True
当我对numpy
数组执行np.isreal
时.
np.isreal( np.array(["hello","world",{"a":5,"b":6,"c":8},"usa","india",{"d":9,"e":10,"f":11}]))
Out[813]: array([ True, True, True, True, True, True], dtype=bool)
我必须在错误的用例中使用np.isreal
,但是您可以帮助我 为什么结果不同 吗?
I must using the np.isreal
in the wrong use case, But can you help me about why the result is different ?
推荐答案
部分答案是 isreal
仅打算像数组一样用作第一个参数.
A partial answer is that isreal
is only intended to be used on array-like as the first argument.
您要使用 isrealobj
在每个元素上获得您在此处看到的行为:
You want to use isrealobj
on each element to get the bahavior you see here:
In [11]: a = np.array(["hello","world",{"a":5,"b":6,"c":8},"usa","india",{"d":9,"e":10,"f":11}])
In [12]: a
Out[12]:
array(['hello', 'world', {'a': 5, 'b': 6, 'c': 8}, 'usa', 'india',
{'d': 9, 'e': 10, 'f': 11}], dtype=object)
In [13]: [np.isrealobj(aa) for aa in a]
Out[13]: [True, True, True, True, True, True]
In [14]: np.isreal(a)
Out[14]: array([ True, True, True, True, True, True], dtype=bool)
这确实留下了一个问题,np.isreal
对不像数组的东西做什么?
That does leave the question, what does np.isreal
do on something that isn't array-like e.g.
In [21]: np.isrealobj("")
Out[21]: True
In [22]: np.isreal("")
Out[22]: False
In [23]: np.isrealobj({})
Out[23]: True
In [24]: np.isreal({})
Out[24]: True
事实证明,这源于.imag
,因为测试isreal
的行为是:
It turns out this stems from .imag
since the test that isreal
does is:
return imag(x) == 0 # note imag == np.imag
就是这样.
In [31]: np.imag(a)
Out[31]: array([0, 0, 0, 0, 0, 0], dtype=object)
In [32]: np.imag("")
Out[32]:
array('',
dtype='<U1')
In [33]: np.imag({})
Out[33]: array(0, dtype=object)
这会在数组上查找.imag
属性.
This looks up the .imag
attribute on the array.
In [34]: np.asanyarray("").imag
Out[34]:
array('',
dtype='<U1')
In [35]: np.asanyarray({}).imag
Out[35]: array(0, dtype=object)
我不确定为什么尚未在字符串大小写中设置此值...
I'm not sure why this isn't set in the string case yet...
这篇关于np.isreal行为在pandas.DataFrame和numpy.array中有所不同的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!