获取元素大于 X 的 NumPy 数组的行号

让我们看看如何获取至少有一项大于指定值 X 的 numpy 数组的行号。因此，为了完成此任务，我们将一起使用 numpy.where() 和 numpy.any() 函数。

Syntax: numpy.where(condition[, x, y])

Return: [ndarray or tuple of ndarrays] If both x and y are specified, the output array contains elements of x where condition is True, and elements from y elsewhere.

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

Return: [ndarray, optional]Output array with same dimensions as Input array, Placed with result

编程需要懂一点英语

例子：

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].

下面是实现：

Python3

# 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),)