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())

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

AmitDiwan

更新于: 2022年2月3日

96 次浏览

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