Python Zero Basics Introduction 4: Sharding of Lists

Continue to learn the related operations of the list from the previous article, mainly learning list sharding and several functions that operate on list elements, which is a supplement to the previous article.

1. List fragmentation
Format: str1=str[start position: end position]
Function: Copy the elements in the specified range in str to str1, that is to say fragmentation What you get is a copy of the original string, not just a label pointing to str. What you get through "=" assignment is just a label of str. That is, the operation on str is the operation on str1, which is similar to the value transfer in Java. and citations.

2. List repetition operator (*)

3. Membership operator (in not in)
Function: Determine whether an element exists in a list

4. List built-in functions
(1)count(): Count the number of times an element appears in a list

(2)index(): Returns the position where the specified element first appears in the list

This function can also be used Add parameters to search within the specified interval.

(3)reverse() function: realize the reversal of list elements

Of course, it can also be realized from the largest Sort by smallest (note that reverse=True is capitalized)

The relevant knowledge about the list is basically over here, and will be sorted out tomorrow A data structure similar to a list - a tuple. Finally, attach today’s code:

print("------列表的分片------")
str1="abcdefg"str2=str1[0:2]print(str2)print("------重复操作符------")
list=["小甲鱼","小布丁","大布丁"]
list=list*3print(list)print("------成员关系操作符------")print("小甲鱼" in list)print("\n")


list1=['123',"华为",["三星","小米"]]print("三星" in list1)print("\n")print("三星" in list1[2])

list2=['1','1','2','3']
num=list2.count('1')print("列表中元素1出现的次数为:%d"%num)
list3=list2[:]print(list3.index('1'))print(list3)
list3.reverse()print(list3)

list4=[2,1,4,3,7,5]print(list4)print("\n")
list4.sort()print(list4)

list4.sort(reverse=True)print(list4)

The above is the content of the shards in the fourth list of zero-based introduction to Python. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!