在NumPy中抑制包含沿特定轴的掩码值的二维数组的行和/或列

要抑制包含掩码值的二维数组的行和/或列，请在NumPy中使用**np.ma.mask_compress_rowcols()**方法。抑制行为由axis参数选择。

  • 如果axis为None，则抑制行和列。
  • 如果axis为0，则仅抑制行。
  • 如果axis为1或-1，则仅抑制列。

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数元素的数组：

arr = np.array([[65, 68, 81], [93, 33, 76], [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，并将其中一些标记为无效：

maskArr = ma.masked_array(arr, mask =[[1, 1, 0], [ 0, 0, 0], [0, 1, 0], [0, 1, 0]])
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)

要抑制包含掩码值的二维数组的行和/或列，请使用np.ma.mask_compress_rowcols()方法。抑制行为由axis参数选择。如果axis为None，则抑制行和列。如果axis为0，则仅抑制行。如果axis为1或-1，则仅抑制列。

print("
Result...
",np.ma.compress_rowcols(maskArr, axis = 1))

示例

import numpy as np
import numpy.ma as ma

# Create an array with int elements using the numpy.array() method
arr = np.array([[65, 68, 81], [93, 33, 76], [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 and mask some of them as invalid
maskArr = ma.masked_array(arr, mask =[[1, 1, 0], [ 0, 0, 0], [0, 1, 0], [0, 1, 0]])
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)

# To suppress the rows and/or columns of a 2-D array that contain masked values, use the np.ma.mask_compress_rowcols() method in Numpy

# The suppression behavior is selected with the axis parameter
# If axis is None, both rows and columns are suppressed.
# If axis is 0, only rows are suppressed.
# If axis is 1 or -1, only columns are suppressed
print("
Result...
",np.ma.compress_rowcols(maskArr, axis = 1))

输出

Array...
[[65 68 81]
[93 33 76]
[73 88 51]
[62 45 67]]

Array type...
int64

Array Dimensions...
2

Our Masked Array
[[-- -- 81]
[93 33 76]
[73 -- 51]
[62 -- 67]]

Our Masked Array type...
int64

Our Masked Array Dimensions...
2

Our Masked Array Shape...
(4, 3)

Elements in the Masked Array...
12

Result...
[[81]
[76]
[51]
[67]]

更新于：2022年2月4日

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