创建可能包含掩码值的数组类,并在 NumPy 中填充掩码值
使用 **ma.MaskedArray()** 方法创建掩码数组。掩码使用“**mask**”参数设置。此处设置为 False。数据类型使用“**dtype**”参数设置。**fill_value** 参数用于在必要时填充掩码值。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无效,要么是布尔数组,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 import numpy.ma as ma
使用 numpy.array() 方法创建具有整型元素的数组 -
arr = np.array([[77, 51, 92], [56, 31, 69], [73, 88, 51], [62, 45, 67]]) print("Array...", arr) print("Array type...", arr.dtype)
获取数组的维度 -
print("Array Dimensions...",arr.ndim)
创建一个掩码数组。掩码使用“mask”参数设置。此处设置为 False。数据类型使用“dtype”参数设置。fill_value 参数用于在必要时填充掩码值 -
maskArr = ma.MaskedArray(arr, mask = [[1, 1, 0], [ 1, 0, 0], [0, 1, 0], [0, 1, 0]], dtype=float, fill_value = 9999) print("Our Masked Array", maskArr) print("Our Masked Array type...", maskArr.dtype)
获取掩码数组的维度 -
print("Our Masked Array Dimensions...",maskArr.ndim)
获取掩码数组的形状 -
print("Our Masked Array Shape...",maskArr.shape)
获取掩码数组的元素数量 -
print("Elements in the Masked Array...",maskArr.size)
显示 fill_value -
print("Result (fill value)...",maskArr.get_fill_value())
示例
# Python ma.MaskedArray - Create an array class with possibly masked values and fill # in the masked values import numpy as np import numpy.ma as ma # Create an array with int elements using the numpy.array() method arr = np.array([[77, 51, 92], [56, 31, 69], [73, 88, 51], [62, 45, 67]]) print("Array...", arr) print("Array type...", arr.dtype) # Get the dimensions of the Array print("Array Dimensions...",arr.ndim) # Create a masked array # The mask is set using the "mask" parameter. Set to False here # The datatype is set using the "dtype" parameter # The fill_value parameter is used to fill in the masked values when necessary maskArr = ma.MaskedArray(arr, mask = [[1, 1, 0], [ 1, 0, 0], [0, 1, 0], [0, 1, 0]], dtype=float, fill_value = 9999) 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) # Displaying the fill_value print("Result (fill value)...",maskArr.get_fill_value())
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输出
Array... [[77 51 92] [56 31 69] [73 88 51] [62 45 67]] Array type... int64 Array Dimensions... 2 Our Masked Array [[-- -- 92.0] [-- 31.0 69.0] [73.0 -- 51.0] [62.0 -- 67.0]] Our Masked Array type... float64 Our Masked Array Dimensions... 2 Our Masked Array Shape... (4, 3) Elements in the Masked Array... 12 Result (fill value)... 9999.0
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