python numpy.percentile()

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

语法 : numpy.percentile(arr, n, axis=None, out=None)
参数 :
arr :输入阵列。
n :百分值。
axis :我们想沿着这个轴来计算百分位值。否则，它将认为Arr是平坦的（在所有轴上工作）。 axis = 0意味着沿列工作， axis = 1意味着沿行工作。
out :不同的数组，我们要把结果放在其中。该数组必须具有与预期输出相同的尺寸。
返回 :数组的第n个百分位数（如果轴为零，则为标量值），或者沿指定轴的百分位数的数组。

**代码 #1 : **

# 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 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 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.]]