檢查 NumPy 中掩碼陣列中哪個元素小於給定值

要檢查掩碼陣列中哪個元素小於給定值，請使用 **ma.MaskedArray.__lt__()** 方法。返回值為布林型別，即 True 和 False。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。

NumPy 提供了全面的數學函式、隨機數生成器、線性代數例程、傅立葉變換等。它支援各種硬體和計算平臺，並且可以很好地與分散式、GPU 和稀疏陣列庫配合使用。

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([[55, 85, 68, 84], [67, 33, 39, 53], [29, 88, 51, 37], [56, 45, 99, 85]])
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，並將其中一些標記為無效 -

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

要比較的值 -

val = 61
print("
The given value to be compared with the masked array elements...
",val)

要檢查掩碼陣列中哪個元素小於給定值，請使用 ma.MaskedArray.__lt__() 方法。返回值為布林型別，即 True 和 False。對於小於給定值 val 的每個陣列元素，都返回 True -

print("
Display True for each element less than the given value val...
", maskArr.__lt__(val))

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([[55, 85, 68, 84], [67, 33, 39, 53], [29, 88, 51, 37], [56, 45, 99, 85]])
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, 1, 0], [0, 0, 0, 1], [0, 1, 0, 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)

# The value to be compared
val = 61
print("
The given value to be compared with the masked array elements...
",val)

# To check which element in a masked array is less than the given value, use the ma.MaskedArray.__lt__() method
# Returns with boolean type i.e. True and False.
# True is returned for every array element less than the given value val
print("
Display True for each element less than the given value val...
", maskArr.__lt__(val))

輸出

Array...
[[55 85 68 84]
[67 33 39 53]
[29 88 51 37]
[56 45 99 85]]

Array type...
int64

Array Dimensions...
2

Our Masked Array
[[-- -- 68 84]
[67 33 -- 53]
[29 88 51 --]
[56 -- 99 85]]

Our Masked Array type...
int64

Our Masked Array Dimensions...
2

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

Elements in the Masked Array...
16

The given value to be compared with the masked array elements...
61

Display True for each element less than the given value val...
[[-- -- False False]
[False True -- True]
[True False True --]
[True -- False False]]

更新於: 2022-02-22

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