在 Numpy 中計算軸 1 上的掩蓋元素數量
要計算軸 1 上的掩蓋元素數量,可以使用ma.MaskedArray.count_masked() 方法。軸使用“axis”引數進行設定。該方法返回掩蓋元素的總數(axis=None)或給出軸的每個切片的掩蓋元素數量。
axis 引數是要計算的軸。如果為 None(預設值),則使用陣列的展平版本。
步驟
首先,匯入所需的庫 -
import numpy as np import numpy.ma as ma
使用 numpy.arange() 方法建立一個含有 int 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) print("
Our Array type...
", arr.dtype)
獲取陣列的形狀 -
print("
Our Masked Array Shape...
",arr.shape)
獲取陣列的元素數量 -
print("
Elements in the Masked Array...
",arr.size)
建立掩蓋陣列 -
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
若要計算特定軸上的掩蓋元素數量,請使用 ma.MaskedArray.count_masked() 方法。軸使用“axis”引數進行設定 -
print("
Result (number of masked elements)...
",ma.count_masked(arr, axis = 1))
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 # To count the number of masked elements along specific axis, use the ma.MaskedArray.count_masked() method # The axis is set using the "axis" parameter print("
Result (number of masked elements)...
",ma.count_masked(arr, axis = 1))
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 Result (number of masked elements)... [1 1 2 3]
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