在 Numpy 中沿軸 0 連線一系列掩碼陣列

要連線一系列掩碼陣列，請在 Python Numpy 中使用 **ma.concatenate()** 方法。軸是使用“**axis**”引數設定的。這裡，我們設定了軸 0。

引數是必須具有相同形狀的陣列，除了對應於軸的維度（預設情況下為第一個）之外。軸是沿其連線陣列的軸。預設值為 0。該函式返回連線後的陣列，並保留任何掩碼條目。

掩碼陣列是標準 numpy.ndarray 和掩碼的組合。掩碼要麼是 nomask，表示關聯陣列的任何值均無效，要麼是布林陣列，用於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

建立陣列 1，一個使用 numpy.arange() 方法的 3x3 陣列，其中包含 int 元素 -

arr1 = np.arange(9).reshape((3,3))
print("Array1...
", arr1)
print("
Array type...
", arr1.dtype)

建立掩碼陣列 1 -

arr1 = ma.array(arr1)

掩碼陣列 1 -

arr1[0, 1] = ma.masked
arr1[1, 1] = ma.masked

顯示掩碼陣列 1 -

print("
Masked Array1...
",arr1)

建立陣列 2，另一個使用 numpy.arange() 方法的 3x3 陣列，其中包含 int 元素"

arr2 = np.arange(9).reshape((3,3))
print("
Array2...
", arr2)
print("
Array type...
", arr2.dtype)

建立掩碼陣列 2 -

arr2 = ma.array(arr2)

掩碼陣列 2 -

arr2[2, 1] = ma.masked
arr2[2, 2] = ma.masked

顯示掩碼陣列 2 -

print("
Masked Array2...
",arr2)

要連線一系列掩碼陣列，請在 Python Numpy 中使用 ma.concatenate() 方法。軸是使用“axis”引數設定的。這裡，我們設定了軸 0 -

print("
Result of concatenation...
",ma.concatenate([arr1, arr2], axis = 0))

示例

# Python ma.MaskedArray - Concatenate a sequence of masked arrays along axis 0

import numpy as np
import numpy.ma as ma

# Array 1
# Creating a 3x3 array with int elements using the numpy.arange() method
arr1 = np.arange(9).reshape((3,3))
print("Array1...
", arr1)
print("
Array type...
", arr1.dtype)

# Get the dimensions of the Array
print("
Array Dimensions...
",arr1.ndim)

# Get the shape of the Array
print("
Our Array Shape...
",arr1.shape)

# Get the number of elements of the Array
print("
Elements in the Array...
",arr1.size)

# Create a masked array
arr1 = ma.array(arr1)

# Mask Array1
arr1[0, 1] = ma.masked
arr1[1, 1] = ma.masked

# Display Masked Array 1
print("
Masked Array1...
",arr1)

# Array 2
# Creating another 3x3 array with int elements using the numpy.arange() method
arr2 = np.arange(9).reshape((3,3))
print("
Array2...
", arr2)
print("
Array type...
", arr2.dtype)

# Get the dimensions of the Array
print("
Array Dimensions...
",arr2.ndim)

# Get the shape of the Array
print("
Our Array Shape...
",arr2.shape)

# Get the number of elements of the Array
print("
Elements in the Array...
",arr2.size)

# Create a masked array
arr2 = ma.array(arr2)

# Mask Array2
arr2[2, 1] = ma.masked
arr2[2, 2] = ma.masked

# Display Masked Array 2
print("
Masked Array2...
",arr2)

# To concatenate a sequence of arrays, use the ma.concatenate() method in Python Numpy
print("
Result of concatenation...
",ma.concatenate([arr1, arr2], axis = 0))

輸出

Array1...
[[0 1 2]
[3 4 5]
[6 7 8]]

Array type...
int64

Array Dimensions...
2

Our Array Shape...
(3, 3)

Elements in the Array...
9

Masked Array1...
[[0 -- 2]
[3 -- 5]
[6 7 8]]

Array2...
[[0 1 2]
[3 4 5]
[6 7 8]]

Array type...
int64

Array Dimensions...
2

Our Array Shape...
(3, 3)

Elements in the Array...
9

Masked Array2...
[[0 1 2]
[3 4 5]
[6 -- --]]

Result of concatenation...
[[0 -- 2]
[3 -- 5]
[6 7 8]
[0 1 2]
[3 4 5]
[6 -- --]]

AmitDiwan

更新於: 2022-02-03

93 次瀏覽

開啟你的 職業生涯

透過完成課程獲得認證

開始學習