使用Python對掩碼陣列的每個元素進行異或運算


要對掩碼陣列的每個元素與給定的標量值進行異或運算,請在Python NumPy中使用**ma.MaskedArray.__xor__()**方法。掩碼陣列是標準numpy.ndarray和掩碼的組合。掩碼要麼是nomask(表示關聯陣列的無任何無效值),要麼是一個布林陣列,它決定關聯陣列的每個元素是否有效。

NumPy 提供了全面的數學函式、隨機數生成器、線性代數例程、傅立葉變換等等。它支援各種硬體和計算平臺,並且與分散式、GPU和稀疏陣列庫相容良好。

步驟

首先,匯入所需的庫:

import numpy as np
import numpy.ma as ma

使用numpy.array()方法建立一個包含整型元素的陣列:

arr = np.array([[8, 6, 1, 4], [6, 3, 9, 5], [9, 8, 1, 3], [5, 4, 7, 5]])
print("Array...
", arr) print("
Array type...
", arr.dtype)

獲取陣列的維度:

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

建立一個掩碼陣列,並將其中一些標記為無效:

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)

獲取掩碼陣列的維度:

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

獲取掩碼陣列的形狀:

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

獲取掩碼陣列的元素個數:

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

標量值:

val = 3
print("
The given value..
",val)

要對掩碼陣列的每個元素與給定的標量值進行異或運算,請使用ma.MaskedArray.__xor__()方法:

print("
Resultant Array...
",maskArr.__xor__(val))

示例

# Python ma.MaskedArray - XOR every element of a masked array by a given scalar value

import numpy as np
import numpy.ma as ma

# Create an array with int elements using the numpy.array() method
arr = np.array([[8, 6, 1, 4], [6, 3, 9, 5], [9, 8, 1, 3], [5, 4, 7,5]])
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 scalar val = 3 print("
The given value..
",val) # To XOR every element of a masked array by a given scalar value, # use the ma.MaskedArray.__xor__() method print("
Resultant Array...
",maskArr.__xor__(val))

輸出

Array...
[[8 6 1 4]
[6 3 9 5]
[9 8 1 3]
[5 4 7 5]]

Array type...
int64

Array Dimensions...
2

Our Masked Array
[[-- -- 1 4]
[6 3 -- 5]
[9 8 1 --]
[5 -- 7 5]]

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..
3

Resultant Array...
[[-- -- 2 7]
[5 0 -- 6]
[10 11 2 --]
[6 -- 4 6]]

更新於:2022年2月3日

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