python中的numpy.sum()用法详细介绍

numpy.sum(arr, axis, dtype, out):此函数返回指定轴上的数组元素的总和。

参数:arr:输入数组。 axis:我们要沿其计算总和值的轴。否则, 它将认为arr是平坦的(在所有轴上均有效)。 axis = 0表示沿列, 而axis = 1表示沿行。 out:要在其中放置结果的另一个数组。数组必须具有与预期输出相同的尺寸。默认为无。 initial:[标量, 可选]和的起始值。返回值:数组元素的总和(如果轴不存在, 则为标量值)或具有沿指定轴的总和的数组。
代码1:
# Python Program illustrating # numpy.sum() method import numpy as np # 1D array arr = [ 20 , 2 , . 2 , 10 , 4 ]print ( "\nSum of arr : " , np. sum (arr)) print ( "Sum of arr(uint8) : " , np. sum (arr, dtype = np.uint8)) print ( "Sum of arr(float32) : " , np. sum (arr, dtype = np.float32))print ( "\nIs np.sum(arr).dtype == np.uint : " , np. sum (arr).dtype = = np.uint) print ( "Is np.sum(arr).dtype == np.float : " , np. sum (arr).dtype = = np. float )

输出如下:
Sum of arr :36.2 Sum of arr(uint8) :36 Sum of arr(float32) :36.2Is np.sum(arr).dtype == np.uint :False Is np.sum(arr).dtype == np.uint :True

代码2:
# Python Program illustrating # numpy.sum() method import numpy as np # 2D array arr = [[ 14 , 17 , 12 , 33 , 44 ], [ 15 , 6 , 27 , 8 , 19 ], [ 23 , 2 , 54 , 1 , 4 , ]]print ( "\nSum of arr : " , np. sum (arr)) print ( "Sum of arr(uint8) : " , np. sum (arr, dtype = np.uint8)) print ( "Sum of arr(float32) : " , np. sum (arr, dtype = np.float32))print ( "\nIs np.sum(arr).dtype == np.uint : " , np. sum (arr).dtype = = np.uint) print ( "Is np.sum(arr).dtype == np.uint : " , np. sum (arr).dtype = = np. float )

输出如下:
Sum of arr :279 Sum of arr(uint8) :23 Sum of arr(float32) :279.0Is np.sum(arr).dtype == np.uint :False Is np.sum(arr).dtype == np.uint :False

代码3:
# Python Program illustrating # numpy.sum() method import numpy as np # 2D array arr = [[ 14 , 17 , 12 , 33 , 44 ], [ 15 , 6 , 27 , 8 , 19 ], [ 23 , 2 , 54 , 1 , 4 , ]]print ( "\nSum of arr : " , np. sum (arr)) print ( "Sum of arr(axis = 0) : " , np. sum (arr, axis = 0 )) print ( "Sum of arr(axis = 1) : " , np. sum (arr, axis = 1 ))print ( "\nSum of arr (keepdimension is True): \n" , np. sum (arr, axis = 1 , keepdims = True ))

【python中的numpy.sum()用法详细介绍】输出如下:
Sum of arr :279 Sum of arr(axis = 0) :[52 25 93 42 67] Sum of arr(axis = 1) :[1207584]Sum of arr (keepdimension is True): [[120] [ 75] [ 84]]

首先, 你的面试准备可通过以下方式增强你的数据结构概念:Python DS课程。

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