返回 NumPy 中一維陣列未掩蓋塊對應的切片列表


要返回與一維陣列未掩蓋塊對應的切片列表,請使用 Python NumPy 中的 **ma.clump_unmasked()**。“塊”定義為陣列的連續區域。返回切片列表,每個切片對應陣列中一個連續的未掩蓋元素區域。

掩碼陣列是標準 numpy.ndarray 和掩碼的組合。掩碼要麼是 nomask(表示關聯陣列中沒有無效值),要麼是布林陣列,它確定關聯陣列的每個元素的值是否有效。

步驟

首先,匯入所需的庫:

import numpy as np
import numpy.ma as ma

使用 numpy.array() 方法建立一個包含整型元素的陣列:

arr = np.array([65, 68, 81, 93, 33, 39, 62, 45, 67])
print("Array...
", arr) print("
Array type...
", arr.dtype)

獲取陣列的維度:

print("
Array Dimensions...
",arr.ndim)

建立一個掩碼陣列並將其中一些元素標記為無效:

maskArr = ma.masked_array(arr, mask =[1, 1, 0, 1, 0, 0, 0, 1, 0])
print("
Our Masked Array
", maskArr) print("
Our Masked Array type...
", maskArr.dtype)

獲取掩碼陣列的維度:

print("
Our Masked Array Dimensions...
",maskArr.ndim)

獲取掩碼陣列的形狀:

print("
Our Masked Array Shape...
",maskArr.shape)

獲取掩碼陣列的元素個數:

print("
Elements in the Masked Array...
",maskArr.size)

返回一個布林值,指示資料是否連續:

print("
Check whether the data is contiguous?
",maskArr.iscontiguous())

要返回與一維陣列未掩蓋塊對應的切片列表,請使用 ma.clump_unmasked()。“塊”定義為陣列的連續區域:

print("
Result...
",np.ma.clump_unmasked(maskArr))

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, 39, 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, 1, 0, 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) # Return a boolean indicating whether the data is contiguous print("
Check whether the data is contiguous?
",maskArr.iscontiguous()) # To return a list of slices corresponding to the unmasked clumps of a 1-D array, use the ma.clump_unmasked() in Python Numpy # A "clump" is defined as a contiguous region of the array. print("
Result...
",np.ma.clump_unmasked(maskArr))

輸出

Array...
[65 68 81 93 33 39 62 45 67]

Array type...
int64

Array Dimensions...
1

Our Masked Array
[-- -- 81 -- 33 39 62 -- 67]

Our Masked Array type...
int64

Our Masked Array Dimensions...
1

Our Masked Array Shape...
(9,)

Elements in the Masked Array...
9

Check whether the data is contiguous?
True

Result...
[slice(2, 3, None), slice(4, 7, None), slice(8, 9, None)]

更新於:2022年2月4日

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