Python numpy.nanmin()

numpy.nanmin()函数用于返回数组的最小值或沿数组的任何特定提到的轴返回最小值，忽略任何Nan值。

语法 : numpy.nanmin(arr, axis=None, out=None)
参数 :
arr :输入阵列。
axis :我们想要最小值的坐标轴。否则，它将认为Arr是平坦的（对所有轴都有效）。 axis = 0意味着沿列
and axis = 1 means working along the row.
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 :数组的最小值（如果没有轴，则为标量值）或沿指定轴的最小值数组。

**代码 #1 : **

# Python Program illustrating 
# numpy.nanmin() method 
    
import numpy as np
    
# 1D array 
arr = [1, 2, 7, 0, np.nan]
print("arr : ", arr) 
print("Min of arr : ", np.amin(arr))
  
# nanmin ignores NaN values. 
print("nanMin of arr : ", np.nanmin(arr))

输出 :

arr :  [1, 2, 7, 0, nan]
Min of arr :  nan
nanMin of arr :  0.0

代码 #2 :

# Python Program illustrating 
# numpy.nanmin() method 
  
import numpy as np
  
# 2D array 
arr = [[np.nan, 17, 12, 33, 44],  
       [15, 6, 27, 8, 19]] 
print("\narr : \n", arr) 
     
# Minimum of the flattened array 
print("\nMin of arr, axis = None : ", np.nanmin(arr)) 
     
# Minimum along the first axis 
# axis 0 means vertical 
print("Min of arr, axis = 0 : ", np.nanmin(arr, axis = 0)) 
     
# Minimum along the second axis 
# axis 1 means horizontal 
print("Min of arr, axis = 1 : ", np.nanmin(arr, axis = 1))  

输出 :

arr : 
 [[14, 17, 12, 33, 44], [15, 6, 27, 8, 19]]

Min of arr, axis = None :  6
Min of arr, axis = 0 :  [14  6 12  8 19]
Min of arr, axis = 1 :  [12  6]

代码 #3 :

# Python Program illustrating 
# numpy.nanmin() method 
  
import numpy as np
  
arr1 = np.arange(5) 
print("Initial arr1 : ", arr1)
   
# using out parameter
np.nanmin(arr, axis = 0, out = arr1)
   
print("Changed arr1(having results) : ", arr1)

输出 :

Initial arr1 :  [0 1 2 3 4]
Changed arr1(having results) :  [14  6 12  8 19]