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insert()是Python中的内置函数,可将给定元素插入列表中的给定索引。
用法:
list_name.insert(index, element)
参数:
index - the index at which the element has to be inserted.
element - the element to be inserted in the list.
返回值:
This method does not return any value but
it inserts the given element at the given index.
错误:
If anything other then a list is used with
insert(), then it returns an AttributeError.
注意:如果给定索引> = length(list),则它将插入列表的末尾。
代码1:
# Python3 program for use
# of insert() method
list1 = [ 1, 2, 3, 4, 5, 6, 7 ]
# insert 10 at 4th index
list1.insert(4, 10)
print(list1)
list2 = ['a', 'b', 'c', 'd', 'e']
# insert z at the front of the list
list2.insert(0, 'z')
print(list2)
输出:
[1, 2, 3, 4, 10, 5, 6, 7]
['z', 'a', 'b', 'c', 'd', 'e']
代码2:
# Python3 program for error
# of insert() method
# attribute error
string = "1234567"
string.insert(10, 1)
print(string)
输出:
Traceback (most recent call last):
File "/home/2fe54bd8723cd0ae89a17325da8b2eb5.py", line 7, in
string.insert(10, 1)
AttributeError:'str' object has no attribute 'insert'
实际应用:
在任何元素之前的列表中插入:
代码3:
# Python3 program for Insertion in a list
# before any element using insert() method
list1 = [ 1, 2, 3, 4, 5, 6 ]
# Element to be inserted
element = 13
# Element to be inserted before 3
beforeElement = 3
# Find index
index = list1.index(beforeElement)
# Insert element at beforeElement
list1.insert(index, element)
print(list1)
输出:
[1, 2, 13, 3, 4, 5, 6]