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]]
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