在 NumPy 中返回两个掩码数组的外积
要返回两个掩码数组的外积,请在 Python NumPy 中使用 **ma.outer()** 方法。第一个参数是输入向量。如果输入不是一维的,则将其展平。第二个参数是第二个输入向量。如果输入不是一维的,则将其展平。
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有效,要么是一个布尔数组,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
使用 numpy.arange() 方法创建 Array1,一个包含整数元素的 3x3 数组 -
arr1 = np.arange(9).reshape((3,3)) print("Array1...", arr1) print("Array type...", arr1.dtype)
创建掩码数组 1 -
arr1 = ma.array(arr1)
掩码 Array1 -
arr1[0, 1] = ma.masked arr1[1, 1] = ma.masked
显示掩码数组 1 -
print("Masked Array1...",arr1)
使用 numpy.arange() 方法创建 Array2,包含整数元素 -
arr2 = np.arange(9).reshape((3,3)) print("Array2...", arr2) print("Array type...", arr2.dtype)
创建掩码数组 2 -
arr2 = ma.array(arr2)
掩码 Array2 -
arr2[2, 1] = ma.masked arr2[2, 2] = ma.masked
显示掩码数组 2 -
print("Masked Array2...",arr2)
要返回两个掩码数组的外积,请在 Python NumPy 中使用 ma.outer() 方法。掩码值将替换为 0 -
print("Result...",np.ma.outer(arr1, arr2))
示例
import numpy as np import numpy.ma as ma # Array 1 # Creating a 3x3 array with int elements using the numpy.arange() method arr1 = np.arange(9).reshape((3,3)) print("Array1...", arr1) print("Array type...", arr1.dtype) # Get the dimensions of the Array print("Array Dimensions...",arr1.ndim) # Get the shape of the Array print("Our Array Shape...",arr1.shape) # Get the number of elements of the Array print("Elements in the Array...",arr1.size) # Create a masked array arr1 = ma.array(arr1) # Mask Array1 arr1[0, 1] = ma.masked arr1[1, 1] = ma.masked # Display Masked Array 1 print("Masked Array1...",arr1) # Array 2 # Creating another 3x3 array with int elements using the numpy.arange() method arr2 = np.arange(9).reshape((3,3)) print("Array2...", arr2) print("Array type...", arr2.dtype) # Get the dimensions of the Array print("Array Dimensions...",arr2.ndim) # Get the shape of the Array print("Our Array Shape...",arr2.shape) # Get the number of elements of the Array print("Elements in the Array...",arr2.size) # Create a masked array arr2 = ma.array(arr2) # Mask Array2 arr2[2, 1] = ma.masked arr2[2, 2] = ma.masked # Display Masked Array 2 print("Masked Array2...",arr2) # To return the outer product of two masked arrays, use the ma.outer() method in Python Numpy # The masked values are replaced by 0 print("Result...",np.ma.outer(arr1, arr2))
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输出
Array1... [[0 1 2] [3 4 5] [6 7 8]] Array type... int64 Array Dimensions... 2 Our Array Shape... (3, 3) Elements in the Array... 9 Masked Array1... [[0 -- 2] [3 -- 5] [6 7 8]] Array2... [[0 1 2] [3 4 5] [6 7 8]] Array type... int64 Array Dimensions... 2 Our Array Shape... (3, 3) Elements in the Array... 9 Masked Array2... [[0 1 2] [3 4 5] [6 -- --]] Result... [[0 0 0 0 0 0 0 -- --] [-- -- -- -- -- -- -- -- --] [0 2 4 6 8 10 12 -- --] [0 3 6 9 12 15 18 -- --] [-- -- -- -- -- -- -- -- --] [0 5 10 15 20 25 30 -- --] [0 6 12 18 24 30 36 -- --] [0 7 14 21 28 35 42 -- --] [0 8 16 24 32 40 48 -- --]]
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