在NumPy中创建可能包含掩码值的数组类,并设置不同的输出dtype
使用**ma.MaskedArray()**方法创建一个掩码数组。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。掩码数组是标准numpy.ndarray和掩码的组合。掩码要么是nomask,表示关联数组的无任何值无效,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()方法创建一个包含整型元素的数组:
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:
maskArr = ma.MaskedArray(arr, mask = False, dtype=float)
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)
示例
# Python ma.MaskedArray - Create an array class with possibly masked values and set a different dtype of output
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
maskArr = ma.MaskedArray(arr, mask = False, dtype=float)
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)输出
Array... [[77 51 92] [56 31 69] [73 88 51] [62 45 67]] Array type... int64 Array Dimensions... 2 Our Masked Array [[77.0 51.0 92.0] [56.0 31.0 69.0] [73.0 88.0 51.0] [62.0 45.0 67.0]] Our Masked Array type... float64 Our Masked Array Dimensions... 2 Our Masked Array Shape... (4, 3) Elements in the Masked Array... 12
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