获取元素大于X的NumPy数组的行数

让我们看看如何获得一个数组中至少有一项大于指定值X的行数。因此，为了完成这项任务，我们将同时使用numpy.where()和numpy.any()函数。

语法: numpy.where(condition[, x, y])

返回： [ndarray or tuple of ndarrays] 如果同时指定了x和y，输出数组包含条件为True的x的元素，以及其他地方的y的元素。

语法: numpy.any(a, axis = None, out = None, keepdims = class numpy._globals._NoValue at 0x40ba726c)

返回： [ndarray, optional]与输入数组尺寸相同的输出数组，与结果放在一起。

示例 :

Arr = [[1,2,3,4,5], 
      [10,-3,30,4,5], 
      [3,2,5,-4,5], 
      [9,7,3,6,5]] 
and **X = 6** then output is **[ 0, 2 ]**.

Here, 
[[1,2,3,4,5],
no element is greater than 6 so output is [0].

[10,-3,30,4,5],
10 is greater than 6 so output is [0].

[3,2,5,-4,5],
no element is greater than 6 so output is [0, 2].

[4, **7** ,3,6,5]]
7 is greater than 6 so output is [0, 2].

以下是实施情况。

# importing library
import numpy
  
# create numpy array
arr = numpy.array([[1, 2, 3, 4, 5],
                  [10, -3, 30, 4, 5],
                  [3, 2, 5, -4, 5],
                  [9, 7, 3, 6, 5] 
                 ])
  
# declare specified value
X = 6
  
# view array
print("Given Array:\n", arr)
  
# finding out the row numbers
output  = numpy.where(numpy.any(arr > X,
                                axis = 1))
  
# view output
print("Result:\n", output)

输出:

Given Array:
[[ 1  2  3  4  5]
[10 -3 30  4  5]
[ 3  2  5 -4  5]
[ 9  7  3  6  5]]
Result:
(array([1, 3], dtype=int64),)