Python 如何反向迭代序列

Python序列包括字符串、列表、元组等。我们可以使用不同的方法来合并Python序列的元素。让我们来看一些在反向顺序中迭代列表的示例。

使用while循环反向迭代

示例

在此示例中，我们有一个作为序列的列表，并使用while循环以反向顺序迭代它-

# Creating a List
mylist = ["Jacob", "Harry", "Mark", "Anthony"]

# Displaying the List
print("List = ",mylist)

# Length - 1
i = len(mylist) - 1

# Iterate in reverse order
print("Display the List in Reverse order = ")
while i >= 0 :
   print(mylist[i])
   i -= 1

输出

List =  ['Jacob', 'Harry', 'Mark', 'Anthony']
Display the List in Reverse order = 
Anthony
Mark
Harry
Jacob

使用for循环逆序迭代

示例

在这个示例中，我们有一个列表作为一个序列，并使用for循环以逆序迭代它。

# Creating a List
mylist = ["Jacob", "Harry", "Mark", "Anthony"]

# Displaying the List
print("List = ",mylist)

# Iterate in reverse order
print("Display the List in Reverse order = ")
for i in range(len(mylist) - 1, -1, -1):
   print(mylist[i])

输出

List =  ['Jacob', 'Harry', 'Mark', 'Anthony']
Display the List in Reverse order = 
Anthony
Mark
Harry
Jacob

使用reversed()以逆序迭代

示例

在这个示例中，我们有一个作为序列的列表，并使用reversed()方法以逆序迭代它：

# Creating a List
mylist = ["Jacob", "Harry", "Mark", "Anthony"]

# Displaying the List
print("List = ",mylist)

# Iterate in reverse order using reversed()
print("Display the List in Reverse order = ")
[print (i) for i in reversed(mylist)]

输出

List =  ['Jacob', 'Harry', 'Mark', 'Anthony']
Display the List in Reverse order = 
Anthony
Mark
Harry
Jacob

使用负索引倒序迭代

示例

在这个示例中，我们有一个作为序列的列表，并使用负索引以倒序迭代它。-

# Creating a List
mylist = ["Jacob", "Harry", "Mark", "Anthony"]

# Displaying the List
print("List = ",mylist)

# Iterate in reverse order using negative indexing
print("Display the List in Reverse order = ")
[print (i) for i in mylist[::-1]]

输出

List =  ['Jacob', 'Harry', 'Mark', 'Anthony']
Display the List in Reverse order = 
Anthony
Mark
Harry
Jacob