在 Numpy 中查詢掩碼陣列沿給定軸的連續未掩碼資料

要查詢掩碼陣列沿給定軸的連續未掩碼資料，請在 Python Numpy 中使用 **numpy.ma.notmasked_contiguous**。該方法返回陣列中未掩碼索引的切片（起始和結束索引）列表。如果輸入是二維的並且指定了軸，則結果是一個列表的列表。

軸是執行操作的軸。如果為 None（預設值），則應用於陣列的扁平化版本，這與 flatnotmasked_contiguous 相同。

步驟

首先，匯入所需的庫 -

import numpy as np
import numpy.ma as ma

使用 numpy.array() 方法建立包含整數元素的陣列 -

arr = np.array([[65, 68, 81], [93, 33, 39], [73, 88, 51], [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的某些元素標記為無效 -

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

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())

要查詢掩碼陣列沿給定軸的連續未掩碼資料，請使用 numpy.ma.notmasked_contiguous

print("
Result...
",np.ma.notmasked_contiguous(maskArr, axis = 0))

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], [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], [ 1, 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)

# Return a boolean indicating whether the data is contiguous
print("
Check whether the data is contiguous?
",maskArr.iscontiguous())

# To find contiguous unmasked data in a masked array along the given axis, use the numpy.ma.notmasked_contiguous in Python Numpy
print("
Result...
",np.ma.notmasked_contiguous(maskArr, axis = 0))

輸出

Array...
[[65 68 81]
[93 33 39]
[73 88 51]
[62 45 67]]

Array type...
int64

Array Dimensions...
2

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

Check whether the data is contiguous?
True
Result...
[[slice(2, 4, None)], [slice(1, 2, None)], [slice(0, 4, None)]]

AmitDiwan

更新於: 2022年2月4日

124 次檢視

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