检查 NumPy 中掩码数组中哪个元素等于给定值

要检查掩码数组中哪个元素等于给定值，请使用 **ma.MaskedArray.__eq__()** 方法。对于等于给定值 val 的每个数组元素，都会返回 True。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，要么是布尔值数组，用于确定关联数组的每个元素的值是否有效。

NumPy 提供了全面的数学函数、随机数生成器、线性代数例程、傅里叶变换等等。它支持各种硬件和计算平台，并且与分布式、GPU 和稀疏数组库配合良好。

步骤

首先，导入所需的库 -

import numpy as np
import numpy.ma as ma

使用 numpy.array() 方法创建具有整数元素的数组 -

arr = np.array([[55, 85, 68, 84], [67, 33, 39, 53], [29, 88, 51, 37], [56, 45, 67, 85]])
print("Array...
", arr)
print("
Array type...
", arr.dtype)

获取数组的维度 -

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

创建一个掩码数组并掩盖其中一些为无效 -

maskArr = ma.masked_array(arr, mask =[[1, 1, 0, 0], [ 0, 0, 1, 0], [0, 0, 0, 1], [0, 1, 0, 0]])
print("
Our Masked Array
", maskArr)
print("
Our Masked Array type...
", maskArr.dtype)

获取掩码数组的维度 -

print("
Our Masked Array Dimensions...
",maskArr.ndim)

获取掩码数组的形状 -

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

获取掩码数组的元素数量 -

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

要比较的值 -

val = 67
print("
The given value to be compared with the masked array elements...
",val)

要检查掩码数组中哪个元素等于给定值，请使用 ma.MaskedArray.__eq__() 方法。返回布尔类型，即 True 和 False。对于每个等于给定值 val 的数组元素，都会返回 True -

print("
Display True for each element equal to a given value val...
", maskArr.__eq__(val))

示例

import numpy as np
import numpy.ma as ma

# Create an array with int elements using the numpy.array() method
arr = np.array([[55, 85, 68, 84], [67, 33, 39, 53], [29, 88, 51, 37], [56, 45, 67, 85]])
print("Array...
", arr)
print("
Array type...
", arr.dtype)

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

# Create a masked array and mask some of them as invalid
maskArr = ma.masked_array(arr, mask =[[1, 1, 0, 0], [ 0, 0, 1, 0], [0, 0, 0, 1], [0, 1, 0, 0]])
print("
Our Masked Array
", maskArr)
print("
Our Masked Array type...
", maskArr.dtype)

# Get the dimensions of the Masked Array
print("
Our Masked Array Dimensions...
",maskArr.ndim)

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

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

# The value to be compared
val = 67
print("
The given value to be compared with the masked array elements...
",val)

# To check which element in a masked array is equal to a given value, use the ma.MaskedArray.__eq__() method
# Returns with boolean type i.e. True and False.
# True is returned for every array element equal to a given value val
print("
Display True for each element equal to a given value val...
",
maskArr.__eq__(val))

输出

Array...
[[55 85 68 84]
[67 33 39 53]
[29 88 51 37]
[56 45 67 85]]

Array type...
int64

Array Dimensions...
2

Our Masked Array
[[-- -- 68 84]
[67 33 -- 53]
[29 88 51 --]
[56 -- 67 85]]

Our Masked Array type...
int64

Our Masked Array Dimensions...
2

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

Elements in the Masked Array...
16

The given value to be compared with the masked array elements...
67

Display True for each element equal to a given value val...
[[-- -- False False]
[True False -- False]
[False False False --]
[False -- True False]]

更新于: 2022年2月5日

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