确定输入是否为 NumPy 掩码数组的实例

要确定输入是否为掩码数组的实例，请在 Python NumPy 中使用 **ma.isMaskedArray()** 方法。如果 x 是 MaskedArray 的实例，则此函数返回 True，否则返回 False。任何对象都作为输入被接受。

掩码数组是标准 numpy.ndarray 和掩码的组合。掩码要么是 nomask，表示关联数组的任何值均无效，要么是布尔值的数组，用于确定关联数组的每个元素的值是否有效。

步骤

首先，导入所需的库：

import numpy as np
import numpy.ma as ma

使用 numpy.arange() 方法创建一个包含整数元素的 4x4 数组：

arr = np.arange(16).reshape((4,4))
print("Array...
", arr)
print("
Array type...
", arr.dtype)

获取数组的维度：

print("
Array Dimensions...
",arr.ndim)

获取数组的形状：

print("
Our Masked Array Shape...
",arr.shape)

获取数组的元素数量：

print("
Elements in the Masked Array...
",arr.size)

创建一个掩码数组：

arr = ma.array(arr)
arr[0, 1] = ma.masked
arr[1, 1] = ma.masked
arr[2, 1] = ma.masked
arr[2, 2] = ma.masked
arr[3, 0] = ma.masked
arr[3, 2] = ma.masked
arr[3, 3] = ma.masked

沿特定轴计算掩码元素的数量：

print("
The number of masked elements...
",ma.count_masked(arr, axis = 1))

返回掩码数组的掩码：

print("
The mask of a masked array)...
",ma.getmask(arr))

将掩码数组的数据作为 ndarray 返回：

print("
Data of a masked array as an ndarray...
",ma.getdata(arr))

要确定输入是否为掩码数组的实例，请在 Python NumPy 中使用 ma.isMaskedArray() 方法：

print("
Whether input is an instance of masked array?
",ma.isMaskedArray(arr))

示例

import numpy as np
import numpy.ma as ma

# Creating a 4x4 array with int elements using the numpy.arange() method
arr = np.arange(16).reshape((4,4))
print("Array...
", arr)
print("
Array type...
", arr.dtype)

# Get the dimensions of the Array
print("
Array Dimensions...
",arr.ndim)
print("
Our Array type...
", arr.dtype)

# Get the shape of the Array
print("
Our Masked Array Shape...
",arr.shape)

# Get the number of elements of the Array
print("
Elements in the Masked Array...
",arr.size)

# Create a masked array
arr = ma.array(arr)
arr[0, 1] = ma.masked
arr[1, 1] = ma.masked
arr[2, 1] = ma.masked
arr[2, 2] = ma.masked
arr[3, 0] = ma.masked
arr[3, 2] = ma.masked
arr[3, 3] = ma.masked

# Count the number of masked elements along specific axis
print("
The number of masked elements...
",ma.count_masked(arr, axis = 1))

# Return the mask of a masked array
print("
The mask of a masked array)...
",ma.getmask(arr))

# Return the data of a masked array as an ndarray
print("
Data of a masked array as an ndarray...
",ma.getdata(arr))

# To determine whether input is an instance of masked array, use the ma.isMaskedArray() method in Python Numpy
print("
Whether input is an instance of masked array?
",ma.isMaskedArray(arr))

输出

Array...
[[ 0 1 2 3]
[ 4 5 6 7]
[ 8 9 10 11]
[12 13 14 15]]

Array type...
int64

Array Dimensions...
2

Our Array type...
int64

Our Masked Array Shape...
(4, 4)

Elements in the Masked Array...
16

The number of masked elements...
[1 1 2 3]

The mask of a masked array)...
[[False True False False]
[False True False False]
[False True True False]
[ True False True True]]

Data of a masked array as an ndarray...
[[ 0 1 2 3]
[ 4 5 6 7]
[ 8 9 10 11]
[12 13 14 15]]

Whether input is an instance of masked array?
True

更新于: 2022年2月18日

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