Python 程序反转数组

编写一个 Python 程序来反转给定的 Numpy 数组。我们可以使用带有负值的切片技术来反转 Numpy 数组。在此示例中，我们使用相同的方法反转了数字和字符串数组。

import numpy as np

orgarr = np.array([15, 20, 50, 40, 78, 99, 248])
print("Original Numeric Numpy Array Items = ", orgarr)

revarr = orgarr[::-1]
print("After Reversing Numeric Numpy Array = ", revarr)

orgstrarr = np.array(['UK', 'India', 'USA', 'Japan'])
print("Original String Numpy Array Items = ", orgstrarr)

revstrarr = orgstrarr[::-1]
print("After Reversing String Numpy Array = ", revstrarr)

使用 While 循环反转数组的 Python 程序

此示例使用临时变量来移动数字数组项并反转它们。

import numpy as np

orgarr = np.array([14, 27, 99, 50, 65, 18, 195, 100])

j = len(orgarr) - 1
i = 0

while(i < j):
    temp = orgarr[i]
    orgarr[i] = orgarr[j]
    orgarr[j] = temp
    i += 1
    j -= 1

print(orgarr)

[100 195  18  65  50  99  27  14]

使用函数反转数组

在此 Numpy 数组示例中，我们创建了一个函数（def reverseArray(orgarr, number)），该函数反转传递给它的数组。

# using functions
import numpy as np

def reverseArray(orgarr, number) :
    j = number - 1
    i = 0
    
    while(i < j):
        temp = orgarr[i]
        orgarr[i] = orgarr[j]
        orgarr[j] = temp
        i += 1
        j -= 1


arrList = []
number = int(input("Enter the Total Array Items = "))
for i in range(1, number + 1):
    value = int(input("Enter the %d Array value = " %i))
    arrList.append(value)

orgarr = np.array(arrList)
print("Original  = ", orgarr)

reverseArray(orgarr, number) 
print("After  = ", orgarr)

Enter the Total Array Items = 4
Enter the 1 Array value =  20
Enter the 2 Array value =  40
Enter the 3 Array value =  60
Enter the 4 Array value =  80

Original = [20 40 60 80]
After = [80 60 40 20]

使用递归反转数组项

在此程序中，我们创建了一个递归函数来使用更新后的值反转数组（reverseArray(orgarr, i + 1, j – 1））。

import numpy as np

def reverseArray(orgarr, i, j) :
   if(i < j):
        temp = orgarr[i]
        orgarr[i] = orgarr[j]
        orgarr[j] = temp
        reverseArray(orgarr, i + 1, j - 1)
        

orgarr = np.array([22, 44, 87, 538, 89, 120, 197])
print("Original Numeric Numpy Array Items = ", orgarr)

reverseArray(orgarr, 0, (len(orgarr) - 1))
print("After Reversing Numeric Numpy Array = ", orgarr)

Original Numeric Numpy Array Items = [22, 44, 87, 538, 89, 120, 197]
After Reversing Numeric Numpy Array = [197 120 89 538 87 44 22]