numpy.nanpercentile() in Python

numpy.nanpercentile()function used to compute the nth percentile of the given data (array elements) along the specified axis and ignores nan values.

Syntax : 

numpy.nanpercentile(arr, q, axis=None, out=None) 

Parameters :

• arr :input array. 
• q : 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 :Percentile of the array (a scalar value if axis is none) or array with percentiles of values along specified axis.

Code #1 : Working

Python

# Python Program illustrating
# numpy.nanpercentile() method

import numpy as np

# 1D array
arr = [20, 2, 7, np.nan, 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))

print("\n50th percentile of arr : ",
      np.nanpercentile(arr, 50))
print("25th percentile of arr : ",
       np.nanpercentile(arr, 25))
print("75th percentile of arr : ",
      np.nanpercentile(arr, 75))

Output : 

arr :  [20, 2, 7, nan, 34]
50th percentile of arr :  nan
25th percentile of arr :  nan
75th percentile of arr :  nan

50th percentile of arr :  13.5
25th percentile of arr :  5.75
75th percentile of arr :  23.5

Code #2 : 

Python

# Python Program illustrating
# numpy.nanpercentile() method

import numpy as np

# 2D array
arr = [[14, np.nan, 12, 33, 44],
       [15, np.nan, 27, 8, 19],
       [23, 2, np.nan, 1, 4, ]]
print(& quot
       \narr: \n"
       , arr)

# Percentile of the flattened array
print(& quot
       \n50th Percentile of arr, axis = None : & quot
       ,
       np.percentile(arr, 50))
print(& quot
       \n50th Percentile of arr, axis = None : & quot
       ,
       np.nanpercentile(arr, 50))
print(& quot
       0th Percentile of arr, axis = None : & quot
       ,
       np.nanpercentile(arr, 0))

# Percentile along the axis = 0
print(& quot
       \n50th Percentile of arr, axis = 0 : & quot
       ,
       np.nanpercentile(arr, 50, axis=0))
print(& quot
       0th Percentile of arr, axis = 0 : & quot
       ,
       np.nanpercentile(arr, 0, axis=0))

# Percentile along the axis = 1
print(& quot
       \n50th Percentile of arr, axis = 1 : & quot
       ,
       np.nanpercentile(arr, 50, axis=1))
print(& quot
       0th Percentile of arr, axis = 1 : & quot
       ,
       np.nanpercentile(arr, 0, axis=1))

print(& quot
       \n0th Percentile of arr, axis = 1: \n"
       ,
       np.nanpercentile(arr, 50, axis=1, keepdims=True))
print(& quot
       \n0th Percentile of arr, axis = 1: \n"
       ,
       np.nanpercentile(arr, 0, axis=1, keepdims=True))

Output : 

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

50th Percentile of arr, axis = None :  nan

50th Percentile of arr, axis = None :  14.5
0th Percentile of arr, axis = None :  1.0

50th Percentile of arr, axis = 0 :  [15.   2.  19.5  8.  19. ]
0th Percentile of arr, axis = 0 :  [14.  2. 12.  1.  4.]

50th Percentile of arr, axis = 1 :  [23.5 17.   3. ]
0th Percentile of arr, axis = 1 :  [12.  8.  1.]

0th Percentile of arr, axis = 1 : 
 [[23.5]
 [17. ]
 [ 3. ]]

0th Percentile of arr, axis = 1 : 
 [[12.]
 [ 8.]
 [ 1.]]

Code #3: 

Python

# Python Program illustrating
# numpy.nanpercentile() method

import numpy as np

# 2D array
arr = [[14, np.nan, 12, 33, 44],
       [15, np.nan, 27, 8, 19],
       [23, np.nan, np.nan, 1, 4, ]]
print(& quot
       \narr: \n"
       , arr)
# Percentile along the axis = 1
print(& quot
       \n50th Percentile of arr, axis = 1 : & quot
       ,
       np.nanpercentile(arr, 50, axis=1))
print(& quot
       \n50th Percentile of arr, axis = 0 : & quot
       ,
       np.nanpercentile(arr, 50, axis=0))

Output : 

arr : 
 [[14, nan, 12, 33, 44], [15, nan, 27, 8, 19], [23, nan, nan, 1, 4]]

50th Percentile of arr, axis = 1 :  [23.5 17.   4. ]

50th Percentile of arr, axis = 0 :  [15.   nan 19.5  8.  19. ]
RuntimeWarning: All-NaN slice encountered
  overwrite_input, interpolation)