Python|在numpy数组中用零替换负值

给定numpy数组，任务是将numpy数组中的负值替换为零。让我们看几个这个问题的例子。

方法#1：朴素的方法

# Python code to demonstrate
# to replace negative value with 0
import numpy as np
  
ini_array1 = np.array([1, 2, -3, 4, -5, -6])
  
# printing initial arrays
print("initial array", ini_array1)
  
# code to replace all negative value with 0
ini_array1[ini_array1<0] = 0
  
# printing result
print("New resulting array: ", ini_array1)

输出：

initial array [ 1  2 -3  4 -5 -6]
New resulting array:  [1 2 0 4 0 0]

方法 #2：使用np.where

# Python code to demonstrate
# to replace negative values with 0
import numpy as np
  
ini_array1 = np.array([1, 2, -3, 4, -5, -6])
  
# printing initial arrays
print("initial array", ini_array1)
  
# code to replace all negative value with 0
result = np.where(ini_array1<0, 0, ini_array1)
  
# printing result
print("New resulting array: ", result)

输出：

initial array [ 1  2 -3  4 -5 -6]
New resulting array:  [1 2 0 4 0 0]

方法 #3：使用np.clip

# Python code to demonstrate
# to replace negative values with 0
import numpy as np
  
# supposing maxx value array can hold
maxx = 1000
  
ini_array1 = np.array([1, 2, -3, 4, -5, -6])
  
# printing initial arrays
print("initial array", ini_array1)
  
# code to replace all negative value with 0
result = np.clip(ini_array1, 0, 1000)
  
# printing result
print("New resulting array: ", result)

输出：

initial array [ 1  2 -3  4 -5 -6]
New resulting array:  [1 2 0 4 0 0]

方法#4：将给定数组与一个零数组进行比较，并写入两个数组的最大值作为输出。

# Python code to demonstrate
# to replace negative values with 0
import numpy as np
   
ini_array1 = np.array([1, 2, -3, 4, -5, -6])
   
# printing initial arrays
print("initial array", ini_array1)
   
# Creating a array of 0
zero_array = np.zeros(ini_array1.shape, dtype=ini_array1.dtype)
print("Zero array", zero_array)
  
# code to replace all negative value with 0
ini_array2 = np.maximum(ini_array1, zero_array)
  
# printing result
print("New resulting array: ", ini_array2)

输出：

initial array [ 1  2 -3  4 -5 -6]
Zero array [0 0 0 0 0 0]
New resulting array:  [1 2 0 4 0 0]