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法學判斷輸入是否包含掩碼值
要判斷輸入是否包含掩碼值，可以使用Python Numpy中的ma.is_masked()方法。該方法接受任何物件作為輸入，但除非輸入是包含掩碼值的MaskedArray，否則始終返回False。如果陣列是包含掩碼值的MaskedArray，則返回True；否則返回False。
掩碼陣列是標準numpy.ndarray和掩碼的組合。掩碼要麼是nomask（表示關聯陣列的任何值均有效），要麼是布林陣列，用於確定關聯陣列的每個元素的值是否有效。
步驟
首先，匯入所需的庫：
import numpy as np import numpy.ma as ma
使用numpy.arange()方法建立一個包含整數元素的4x4陣列：
arr = np.arange(16).reshape((4,4))
print("Array...
", arr)
print("
Array type...
", arr.dtype)獲取陣列的維度：
print("
Array Dimensions...
",arr.ndim)
獲取陣列的形狀：
print("
Our Masked Array Shape...
",arr.shape)獲取陣列的元素個數：
print("
Elements in the Masked Array...
",arr.size)
建立一個掩碼陣列：
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
沿特定軸計算掩碼元素的個數：
print("
The number of masked elements...
",ma.count_masked(arr, axis = 1))
返回掩碼陣列的掩碼：
print("
The mask of a masked array)...
",ma.getmask(arr))返回掩碼陣列的資料作為ndarray：
print("
Data of a masked array as an ndarray...
",ma.getdata(arr))
要判斷輸入是否包含掩碼值，可以使用Python Numpy中的ma.is_masked()方法：
print("
Whether input has masked values?
",ma.is_masked(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 has masked values, use the ma.is_masked() method in Python Numpy
print("
Whether input has masked values?
",ma.is_masked(arr))輸出
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 has masked values? True
更新於：2022年2月18日
1K+ 次檢視
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