在NumPy中返回一個包含相同資料但具有新形狀的掩碼陣列


要返回一個包含相同資料但具有新形狀的掩碼陣列,請在NumPy中使用 **ma.MaskedArray.reshape()** 方法。賦予陣列新的形狀而無需更改其資料。新形狀應與原始形狀相容。如果提供的是整數,則結果將是一個長度為該整數的一維陣列。

順序決定了陣列資料是否應按C語言(行主序)或FORTRAN(列主序)順序檢視。返回一個包含相同資料但具有新形狀的掩碼陣列。結果是對原始陣列的檢視;如果無法實現此目的,則會引發ValueError。

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數元素的陣列:

arr = np.array([[49, 85, 45], [67, 33, 59]])
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掩蓋其中一些無效元素:

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

要返回一個包含相同資料但具有新形狀的掩碼陣列,請使用ma.MaskedArray.reshape()方法。賦予陣列新的形狀而無需更改其資料。掩碼陣列的新形狀設定為6x1作為引數。新形狀應與原始形狀相容。如果提供的是整數,則結果將是一個長度為該整數的一維陣列:

print("
Result...
",maskArr.reshape((6,1)))

示例

# Python ma.MaskedArray - Return a masked array containing the same data but with a new shape

import numpy as np
import numpy.ma as ma

# Create an array with int elements using the numpy.array() method
arr = np.array([[78, 85, 51], [56, 33, 97]])
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 # The masked array is 1x6 maskArr = ma.masked_array(arr, mask =[[0, 1, 0, 0, 0, 1]]) 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 return a masked array containing the same data, but with a new shape, use the ma.MaskedArray.reshape() method in Numpy # Give a new shape to the array without changing its data # The new shape of the masked array is set to 6x1 as a parameter # The new shape should be compatible with the original shape. # If an integer is supplied, then the result will be a 1-D array of that length print("
Result...
",maskArr.reshape((6,1)))

輸出

Array...
[[78 85 51]
[56 33 97]]

Array type...
int64

Array Dimensions...
2

Our Masked Array
[[78 -- 51]
[56 33 --]]

Our Masked Array type...
int64

Our Masked Array Dimensions...
2

Our Masked Array Shape...
(2, 3)

Elements in the Masked Array...
6

Result...
[[78]
[--]
[51]
[56]
[33]
[--]]

更新於:2022年2月2日

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