Open In App

np.nanmax() in Python

Last Updated : 29 Nov, 2018
Comments
Improve
Suggest changes
Like Article
Like
Report
numpy.nanmax()function is used to returns maximum value of an array or along any specific mentioned axis of the array, ignoring any Nan value.
Syntax : numpy.nanmax(arr, axis=None, out=None, keepdims = no value) Parameters : arr : Input array. axis : Axis along which we want the max 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. keepdims : If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the original a. Return :maximum array value(a scalar value if axis is none)or array with maximum value along specified axis.
Code #1 : Working Python
# Python Program illustrating 
# numpy.nanmax() method 
  
import numpy as np
  
# 1D array 
arr = [1, 2, 7, 0, np.nan]
print("arr : ", arr) 
print("max of arr : ", np.amax(arr))

# nanmax ignores NaN values. 
print("nanmax of arr : ", np.nanmax(arr))
 
Output :
arr :  [1, 2, 7, 0, nan]
max of arr :  nan
nanmax of arr :  7.0
  Code #2 : Python
import numpy as np

# 2D array 
arr = [[np.nan, 17, 12, 33, 44],  
       [15, 6, 27, 8, 19]] 
print("\narr : \n", arr) 
   
# maximum of the flattened array 
print("\nmax of arr, axis = None : ", np.nanmax(arr)) 
   
# maximum along the first axis 
# axis 0 means vertical 
print("max of arr, axis = 0 : ", np.nanmax(arr, axis = 0)) 
   
# maximum along the second axis 
# axis 1 means horizontal 
print("max of arr, axis = 1 : ", np.nanmax(arr, axis = 1)) 
Output :
arr : 
 [[nan, 17, 12, 33, 44], [15, 6, 27, 8, 19]]

max of arr, axis = None :  44.0
max of arr, axis = 0 :  [15. 17. 27. 33. 44.]
max of arr, axis = 1 :  [44. 27.]
  Code #3 : Python
import numpy as np

arr1 = np.arange(5) 
print("Initial arr1 : ", arr1)
 
# using out parameter
np.nanmax(arr, axis = 0, out = arr1)
 
print("Changed arr1(having results) : ", arr1)  
Output :
Initial arr1 :  [0 1 2 3 4]
Changed arr1(having results) :  [15 17 27 33 44]

Next Article

Similar Reads