Python 删除X数组中的NaN行以及Y数组中的对应行
我有一个带有NaN的X数组,我可以删除带有NaN的行,如下所示:Python 删除X数组中的NaN行以及Y数组中的对应行,python,arrays,numpy,matrix,nan,Python,Arrays,Numpy,Matrix,Nan,我有一个带有NaN的X数组,我可以删除带有NaN的行,如下所示: import numpy as np x = x[~np.isnan(x)] 但我有一个对应的Y数组 assert len(x) == len(y) # True x = x[~np.isnan(x)] assert len(x) == len(y) # False and breaks 如何从Y数组中删除相应的行? 我的X阵列如下所示: >>> x [[ 2.67510434 2.67521927 3.
import numpy as np
x = x[~np.isnan(x)]
但我有一个对应的Y数组
assert len(x) == len(y) # True
x = x[~np.isnan(x)]
assert len(x) == len(y) # False and breaks
如何从Y数组中删除相应的行?
我的X阵列如下所示:
>>> x
[[ 2.67510434 2.67521927 3.49296989 3.80100625 4. 2.83631844]
[ 3.47538057 3.4752436 3.62245715 4.0720535 5. 3.7773169 ]
[ 2.6157049 2.61583852 3.48335887 3.78088813 0. 2.78791096]
...,
[ 3.60408952 3.60391203 3.64328267 4.1156462 5. 3.77933333]
[ 2.66773792 2.66785516 3.49177798 3.7985113 4. 2.83631844]
[ 3.26622238 3.26615124 3.58861468 4.00121327 5. 3.49693169]]
但奇怪的是:
indexes = ~np.isnan(x)
print indexes
[out]:
[[ True True True True True True]
[ True True True True True True]
[ True True True True True True]
...,
[ True True True True True True]
[ True True True True True True]
[ True True True True True True]]
您正在删除NaN项,而不是NaN行。正确的做法是:
mask = ~np.any(np.isnan(x), axis=1)
x = x[mask]
y = y[mask]
要查看两种方法的不同行为,请执行以下操作:
>>> x = np.random.rand(4, 5)
>>> x[[0, 2], [1, 4]] = np.nan
>>> x
array([[ 0.37499461, nan, 0.51254549, 0.5253203 , 0.3955948 ],
[ 0.73817831, 0.70381481, 0.45222295, 0.68540433, 0.76113544],
[ 0.1651173 , 0.41594257, 0.66327842, 0.86836192, nan],
[ 0.70538764, 0.31702821, 0.04876226, 0.53867849, 0.58784935]])
>>> x[~np.isnan(x)] # 1D array with NaNs removed
array([ 0.37499461, 0.51254549, 0.5253203 , 0.3955948 , 0.73817831,
0.70381481, 0.45222295, 0.68540433, 0.76113544, 0.1651173 ,
0.41594257, 0.66327842, 0.86836192, 0.70538764, 0.31702821,
0.04876226, 0.53867849, 0.58784935])
>>> x[~np.any(np.isnan(x), axis=1)] # 2D array with rows with NaN removed
array([[ 0.73817831, 0.70381481, 0.45222295, 0.68540433, 0.76113544],
[ 0.70538764, 0.31702821, 0.04876226, 0.53867849, 0.58784935]]
你是说上面的
y=y[~np.isnan(x)]
?别忘了在这句话之后调用x=x[~np.isnan(x)]
。@xnx,是的,没错,傻我……试试np.mat(x)[~np.isnan(x)]
<代码>np.array(x)[~np.isnan(x)]将返回一个1d数组,而np.mat将保留其维度。它仍然提供索引器:数组索引太多
我得到索引器:数组索引太多
用于你的答案和@xnx方法。你确定x
和y
长度相同吗?牛津字典,参见例如@Bart,我欣赏引用,因此接受索引;然而,这一引文让这个问题悬而未决,因为我是一名科学家,所以我坚持使用“索引”;)@Chris8447~
是反转
运算符,即~np.array([True,False])==np.array([False,True])
。请参阅我的,~np.any(np.isnan(x,axis=1))
返回一个错误:TypeError:“axis”是ufunc“isnan”的无效关键字。
我搞乱了括号的位置,它应该是~np.any(np.isnan(x,axis=1)
。
>>> x = np.random.rand(4, 5)
>>> x[[0, 2], [1, 4]] = np.nan
>>> x
array([[ 0.37499461, nan, 0.51254549, 0.5253203 , 0.3955948 ],
[ 0.73817831, 0.70381481, 0.45222295, 0.68540433, 0.76113544],
[ 0.1651173 , 0.41594257, 0.66327842, 0.86836192, nan],
[ 0.70538764, 0.31702821, 0.04876226, 0.53867849, 0.58784935]])
>>> x[~np.isnan(x)] # 1D array with NaNs removed
array([ 0.37499461, 0.51254549, 0.5253203 , 0.3955948 , 0.73817831,
0.70381481, 0.45222295, 0.68540433, 0.76113544, 0.1651173 ,
0.41594257, 0.66327842, 0.86836192, 0.70538764, 0.31702821,
0.04876226, 0.53867849, 0.58784935])
>>> x[~np.any(np.isnan(x), axis=1)] # 2D array with rows with NaN removed
array([[ 0.73817831, 0.70381481, 0.45222295, 0.68540433, 0.76113544],
[ 0.70538764, 0.31702821, 0.04876226, 0.53867849, 0.58784935]]