Python中的numpy.percentile()

numpy.percentile()函数用于计算给定数据（数组元素）沿指定轴的第 n 个百分位数。

Syntax : numpy.percentile(arr, n, axis=None, out=None) 
Parameters : 
arr :input array. 
n : percentile value. 
axis : axis along which we want to calculate the percentile value. Otherwise, it will consider arr to be flattened(works on all the axis). axis = 0 means along the column and axis = 1 means working along the row. 
out :Different array in which we want to place the result. The array must have same dimensions as expected output. 
Return :nth Percentile of the array (a scalar value if axis is none)or array with percentile values along specified axis. 
 

代码#1：工作

Python

# Python Program illustrating
# numpy.percentile() method
   
import numpy as np
   
# 1D array
arr = [20, 2, 7, 1, 34]
print("arr : ", arr)
print("50th percentile of arr : ",
       np.percentile(arr, 50))
print("25th percentile of arr : ",
       np.percentile(arr, 25))
print("75th percentile of arr : ",
       np.percentile(arr, 75))

输出 ：

arr :  [20, 2, 7, 1, 34]
50th percentile of arr :  7.0
25th percentile of arr :  2.0
75th percentile of arr :  20.0

代码#2：

Python

# Python Program illustrating
# numpy.percentile() method 
 
import numpy as np
 
# 2D array
arr = [[14, 17, 12, 33, 44], 
       [15, 6, 27, 8, 19],
       [23, 2, 54, 1, 4,]]
print("\narr : \n", arr)
    
# Percentile of the flattened array
print("\n50th Percentile of arr, axis = None : ",
      np.percentile(arr, 50))
print("0th Percentile of arr, axis = None : ",
      np.percentile(arr, 0))
    
# Percentile along the axis = 0
print("\n50th Percentile of arr, axis = 0 : ",
      np.percentile(arr, 50, axis =0))
print("0th Percentile of arr, axis = 0 : ",
      np.percentile(arr, 0, axis =0))

输出 ：

arr : 
 [[14, 17, 12, 33, 44], [15, 6, 27, 8, 19], [23, 2, 54, 1, 4]]

50th Percentile of arr, axis = None :  15.0
0th Percentile of arr, axis = None :  1.0

50th Percentile of arr, axis = 0 :  [15.  6. 27.  8. 19.]
0th Percentile of arr, axis = 0 :  [14.  2. 12.  1.  4.]

50th Percentile of arr, axis = 1 :  [17. 15.  4.]
0th Percentile of arr, axis = 1 :  [12.  6.  1.]

代码#3：

Python

# Python Program illustrating
# numpy.percentile() method
 
import numpy as np
 
# 2D array
arr = [[14, 17, 12, 33, 44], 
       [15, 6, 27, 8, 19],
       [23, 2, 54, 1, 4,]]
print("\narr : \n", arr)
 
# Percentile along the axis = 1
print("\n50th Percentile of arr, axis = 1 : ",
      np.percentile(arr, 50, axis =1))
print("0th Percentile of arr, axis = 1 : ",
      np.percentile(arr, 0, axis =1))
  
print("\n0th Percentile of arr, axis = 1 : \n",
      np.percentile(arr, 50, axis =1, keepdims=True))
print("\n0th Percentile of arr, axis = 1 : \n",
      np.percentile(arr, 0, axis =1, keepdims=True))

输出 ：

arr : 
 [[14, 17, 12, 33, 44], [15, 6, 27, 8, 19], [23, 2, 54, 1, 4]]

0th Percentile of arr, axis = 1 : 
 [[17.]
 [15.]
 [ 4.]]

0th Percentile of arr, axis = 1 : 
 [[12.]
 [ 6.]
 [ 1.]]