在 Numpy 中沿負軸減少多維陣列

要沿負軸減少多維陣列，請在 Python Numpy 中使用 **np.ufunc.reduce()** 方法。這裡，我們使用 **add.reduce()** 將其減少到元素的加法。軸使用“axis”引數設定。執行縮減的軸或軸。

**numpy.ufunc** 具有逐元素對整個陣列進行運算的函式。ufunc是用 C 編寫的（為了速度）並與 NumPy 的 ufunc 功能連結到 Python。通用函式（或簡稱 ufunc）是逐元素對 ndarrays 進行運算的函式，支援陣列廣播、型別轉換和幾個其他標準功能。也就是說，ufunc 是一個“向量化”的函式包裝器，它接受固定數量的特定輸入併產生固定數量的特定輸出。

步驟

首先，匯入所需的庫 -

import numpy as np

建立一個多維陣列 -

arr = np.arange(27).reshape((3,3,3))

顯示陣列 -

print("Array...
", arr)

獲取陣列的型別 -

print("
Our Array type...
", arr.dtype)

獲取陣列的維度 -

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

要減少多維陣列，請在 Python Numpy 中使用 np.ufunc.reduce() 方法。這裡，我們使用 multiply.reduce() 將其減少到元素的乘法。軸使用“axis”引數設定。執行縮減的軸或軸。負軸從最後一個軸到第一個軸進行計數 -

print("
Result (multiplication)...
",np.multiply.reduce(arr, axis = -1))

要減少多維陣列，請在 Python Numpy 中使用 np.ufunc.reduce() 方法。這裡，我們使用 add.reduce() 將其減少到元素的加法。軸使用“axis”引數設定。執行縮減的軸或軸。負軸從最後一個軸到第一個軸進行計數 -

print("
Result (addition)...
",np.add.reduce(arr, axis = -1))

示例

import numpy as np

# The numpy.ufunc has functions that operate element by element on whole arrays.
# ufuncs are written in C (for speed) and linked into Python with NumPy’s ufunc facility

# Create a multi-dimensional array
arr = np.arange(27).reshape((3,3,3))

# Display the array
print("Array...
", arr)

# Get the type of the array
print("
Our Array type...
", arr.dtype)

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

# To reduce a multi-dimensional array, use the np.ufunc.reduce() method in Python Numpy
# Here, we have used multiply.reduce() to reduce it to the multiplication of elements elements
# The axis is set using the "axis" parameter
# Axis or axes along which a reduction is performed
# The negative axis it counts from the last to the first axis.
print("
Result (multiplication)...
",np.multiply.reduce(arr, axis = -1))

# To reduce a multi-dimensional array, use the np.ufunc.reduce() method in Python Numpy
# Here, we have used add.reduce() to reduce it to the addition of elements
# The axis is set using the "axis" parameter
# Axis or axes along which a reduction is performed
# The negative axis counts from the last to the first axis.
print("
Result (addition)...
",np.add.reduce(arr, axis = -1))

輸出

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

[[ 9 10 11]
[12 13 14]
[15 16 17]]

[[18 19 20]
[21 22 23]
[24 25 26]]]

Our Array type...
int64

Our Array Dimensions...
3

Result (multiplication)...
[[ 0 60 336]
[ 990 2184 4080]
[ 6840 10626 15600]]

Result (addition)...
[[ 3 12 21]
[30 39 48]
[57 66 75]]

AmitDiwan

更新於: 2022年2月7日

249 次檢視

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